Systems and methods for determining failure of intragastric devices

ABSTRACT

Devices and methods for treating obesity are provided. More particularly, intragastric devices and methods of fabricating, deploying, inflating, locating, tracking, monitoring, deflating, and retrieving the same are provided.

INCORPORATION BY REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 62/151967 filed Apr. 23, 2015. The aforementioned application is incorporated by reference herein in its entirety, and is hereby expressly made a part of this specification.

FIELD

Devices and methods for treating obesity are provided. More particularly, intragastric devices and methods of fabricating, deploying, inflating, locating, tracking, monitoring, deflating, and retrieving the same are provided.

BACKGROUND

Obesity is a major health problem in developed countries. Obesity puts you at greater risk of developing high blood pressure, diabetes and many other serious health problems. In the United States, the complications of being overweight or obese are estimated to affect nearly one in three American adults, with an annual medical cost of over $80 billion and, including indirect costs such as lost wages, a total annual economic cost of over $120 billion. Except for rare pathological conditions, weight gain is directly correlated to overeating.

Noninvasive methods for reducing weight include increasing metabolic activity to burn calories and/or reducing caloric intake, either by modifying behavior or with pharmacological intervention to reduce the desire to eat. Other methods include surgery to reduce the stomach's volume, banding to limit the size of the stoma, and intragastric devices that reduce the desire to eat by occupying space in the stomach.

Intragastric volume-occupying devices provide the patient a feeling of satiety after having eaten only small amounts of food. Thus, the caloric intake is diminished while the person is satisfied with a feeling of fullness. Currently available volume-occupying devices have many shortcomings. For example, complex gastric procedures are required to insert some devices.

U.S. Pat. No. 4,133,315, the contents of which are incorporated herein by reference in their entirety, discloses an apparatus for reducing obesity comprising an inflatable, elastomeric bag and tube combination. The bag can be inserted into the patient's stomach by swallowing. The end of the attached tube distal to the bag remains in the patient's mouth. A second tube is snaked through the nasal cavity and into the patient's mouth. The tube ends located in the patient's mouth are connected to form a continuous tube for fluid communication through the patient's nose to the bag. Alternatively, the bag can be implanted by a gastric procedure. The bag is inflated through the tube to a desired degree before the patient eats so that the desire for food is reduced. After the patient has eaten, the bag is deflated. The tube extends out of the patient's nose or abdominal cavity throughout the course of treatment.

U.S. Pat. Nos. 5,259,399, 5,234,454 and 6,454,785, the contents of which are incorporated herein by reference in their entirety, disclose intragastric volume-occupying devices for weight control that must be implanted surgically.

U.S. Pat. Nos. 4,416,267, 4,485,805, 4,607,618, 4,694,827, 4,723,547, 4,739,758, and 4,899,747 and European Patent No. 246,999, the contents of which are incorporated herein by reference in their entirety, relate to intragastric, volume-occupying devices for weight control that can be inserted endoscopically. Of these, U.S. Pat. Nos. 4,416,267, 4,694,827, 4,739,758 and 4,899,747, the contents of which are incorporated herein by reference in their entirety relate to balloons whose surface is contoured in a certain way to achieve a desired end. In U.S. Pat. Nos. 4,416,267 and 4,694,827, the contents of which are incorporated herein by reference in their entirety, the balloon is torus-shaped with a flared central opening to facilitate passage of solids and liquids through the stomach cavity. The balloon of U.S. Pat. No. 4,694,827, the contents of which are incorporated herein by reference in their entirety, has a plurality of smooth-surfaced convex protrusions. The protrusions reduce the amount of surface area which contacts the stomach wall, thereby reducing the deleterious effects resulting from excessive contact with the gastric mucosa. The protrusions also define channels between the balloon and stomach wall through which solids and liquids may pass. The balloon of U.S. Pat. No. 4,739,758, the contents of which are incorporated herein by reference in their entirety, has blisters on its periphery that prevent it from seating tightly against the cardia or pylorus.

The balloons of U.S. Pat. Nos. 4,899,747 and 4,694,827, the contents of which are incorporated herein by reference in their entirety, are inserted by pushing the deflated balloon and releasably attached tubing down a gastric tube. U.S. Pat. No. 4,723,547, the contents of which are incorporated herein by reference in their entirety discloses a specially adapted insertion catheter for positioning its balloon. In U.S. Pat. No. 4,739,758, the contents of which are incorporated herein by reference in their entirety, the filler tube effects insertion of the balloon. In U.S. Pat. No. 4,485,805, the contents of which are incorporated herein by reference in their entirety, the balloon is inserted into a finger cot that is attached by string to the end of a conventional gastric tube that is inserted down the patient's throat. The balloon of European Patent No. 246,999 is inserted using a gastroscope with integral forceps.

In U.S. Pat. Nos. 4,416,267, 4,485,805, 4,694,827, 4,739,758, and 4,899,747 and European Patent No. 246,999, the contents of which are incorporated herein by reference in their entirety, the balloon is inflated with a fluid from a tube extending down from the patient's mouth. In these patents, the balloon also is provided with a self-sealing hole (U.S. Pat. No. 4,694,827, the contents of which are incorporated herein by reference in their entirety), injection site (U.S. Pat. Nos. 4,416,267 and 4,899,747, the contents of which are incorporated herein by reference in their entirety), self-sealing fill valve (U.S. Pat. No. 4,485,805, the contents of which are incorporated herein by reference in their entirety), self-closing valve (European Patent No. 246,999, the contents of which are incorporated herein by reference in their entirety) or duck-billed valve (U.S. Pat. No. 4,739,758, the contents of which are incorporated herein by reference in their entirety). U.S. Pat. No. 4,723,547, the contents of which are incorporated herein by reference in their entirety, uses an elongated thick plug and the balloon is filled by inserting a needle attached to an air source through the plug.

U.S. Pat. No. 4,607,618, the contents of which are incorporated herein by reference in their entirety, describes a collapsible appliance formed of semi-rigid skeleton members joined to form a collapsible hollow structure. The appliance is not inflatable. It is endoscopically inserted into the stomach using an especially adapted bougie having an ejector rod to release the collapsed appliance. Once released, the appliance returns to its greater relaxed size and shape.

U.S. Pat. No. 5,129,915, the contents of which are incorporated herein by reference in their entirety, relates to an intragastric balloon that is intended to be swallowed and that inflates automatically under the effect of temperature. Three ways that an intragastric balloon might be inflated by a change in temperature are discussed. A composition comprising a solid acid and non-toxic carbonate or bicarbonate is separated from water by a coating of chocolate, cocoa paste or cocoa butter that melts at body temperature. Alternatively, citric acid and an alkaline bicarbonate coated with non-toxic vegetable or animal fat melting at body temperature and which placed in the presence of water, can produce the same result. Lastly, the solid acid and non-toxic carbonate or bicarbonate are isolated from water by an isolation pouch of low-strength synthetic material which it will suffice to break immediately before swallowing the bladder. Breaking the isolation pouches causes the acid, carbonate or bicarbonate and water to mix and the balloon to begin to expand immediately. A drawback of thermal triggering of inflation is that it does not afford the degree of control and reproducibility of the timing of inflation that is desirable and necessary in a safe self-inflating intragastric balloon.

After swallowing, food and oral medicaments typically reach a patient's stomach in under a minute. Food is retained in the stomach on average from one to three hours. However, the residence time is highly variable and dependent upon such factors as the fasting or fed state of the patient. Accordingly, proper timing of inflation of an intragastric balloon is a factor in successful deployment of the intragastric devices of various embodiments. Timing is selected to avoid premature inflation in the esophagus that could lead to an esophageal obstruction or belated inflation that could lead to intestinal obstruction. Similarly, controlled deflation of intragastric balloons is desirable to avoid intestinal obstruction, as is a system of alerting the patient or a caregiver to selected failure mechanisms in an intragastric balloon, e.g., deflation related events.

SUMMARY

There remains a need for a device and method of determining in vivo whether an intragastric balloon device is subject to deflation or other leakage-related events.

A free-floating or tethered intragastric volume-occupying device or devices that maintain volume and/or internal pressure within a predetermined range over time, or which undergoes a predetermined adjustment in volume and/or internal pressure over time, is disclosed. By maintaining a predetermined volume and/or internal pressure, stresses on the device leading to a breach in structural integrity can be minimized, which prevents premature and/or uncontrolled deflation or other device failure. By undergoing a predetermined adjustment in volume and/or internal pressure over time, a preselected volume profile can be obtained to accommodate changes in stomach size over the course of treatment with the device. The devices can be self-inflating (also referred to as automatic inflating) or inflatable (also referred to as manually inflating via a tether), and can include a mechanism to alert a leakage or deflation event.

Volume-occupying devices and methods for manufacturing, deploying, inflating, tracking, locating, deflating and retrieving of such devices are provided. The devices and methods of the preferred embodiments may be employed for treating over weight and obese individuals. Methods employing the device of the preferred embodiments need not utilize invasive procedures, but rather the device may simply be swallowed by a patient, with or without a catheter attached. Once in the stomach of the patient, the device is inflated with a preselected fluid, e.g., a gas, liquid, vapor or mixtures thereof, to a preselected volume. Therefore, the use of one fluid, such as a “gas”, e.g., an initial fill gas, to describe the various embodiments herein, does not preclude the use of other fluids as well. Further, a “fluid,” such as an initial fill fluid, also includes a material or materials in the solid, liquid, vapor, or gas phase that are incorporated within, mixed within, carried within or otherwise entrained in a fluid such as a gas or liquid. A fluid can include, but is not limited to, air, nitrogen, SF₆, other gas(es), vapors, saline solution, pure water, a liquid or vapor under external ambient conditions (e.g., room temperature) that forms a vapor or gas, respectively, at in vivo temperatures (e.g., SF₆), or the like, into the volume-occupying subcomponent and thereby inflate it. The fluid may be or include a variety of other fluid or non-fluid materials as well, including physiologically acceptable fluids, such as aqueous fluids, e.g., water, water with one or more additives (e.g., electrolytes, nutrients, flavorants, colorants, sodium chloride, glucose, etc.), saline solution, or the like. The wall of the device is preselected for its particular fluid, e.g. gas, diffusion properties. Once in the in vivo environment, the gas(es) within the device diffuse out through the wall of the device, and gases diffuse into the device from the in vivo environment. By preselecting the device wall and gas(es) initially employed to inflate the device, taking into account diffusion properties of gases into the device from the in vivo environment, the volume and/or internal pressure of the device can be maintained within a preselected range, or can follow a preselected profile of volume and/or pressure changes. After a predetermined time period, the device can be removed using endoscopic tools or will decrease in volume or deflate so as to pass through the remainder of the patient's digestive tract.

Inflation may be achieved by use of a removable catheter that initially remains in fluid contact with the device after it has been swallowed by the patient. Alternatively, inflation may be achieved by a self-inflation process, e.g., generation of gas in the device once it reaches the stomach by reaction of gas-generating components contained within the device upon swallowing, or by introduction of one or more components in the gas generating process into the device by use of a removable catheter.

The volume-occupying subcomponent of devices may be formed by injection, blow or rotational molding of a flexible, gas-impermeable, biocompatible material, such as, for example, polyurethane, nylon or polyethylene terephthalate. Materials that may be used to control the gas permeability/impermeability of the volume-occupying subcomponent include, but are not limited to, silicon oxide (SiOx), gold or any noble metal, saran, conformal coatings and the like, when it is desired to reduce permeability. To enhance gas-impermeable characteristics of the wall of the device, if desirable, the volume-occupying subcomponent may be further coated with one or more gas-barrier compounds, or be formed of a Mylar polyester film coating or kelvalite, silver or aluminum as a metalized surface to provide a gas impermeable barrier.

In further embodiments, the device employs a delivery state in which the device is packaged such that the device may be swallowed while producing minimal discomfort to the patient. In a delivery state, the device may be packaged into a capsule. Alternatively, the device may be coated with a material operable to confine the device and facilitate swallowing. Various techniques may also be employed to ease swallowing of the device including, for example, wetting, temperature treating, lubricating, and treating with pharmaceuticals such as anesthetics.

The devices incorporate a component or components that enable a patient, caregiver, or physician to determine whether the intragastric balloon has been subject to an event indicative of failure or detrimental to structural integrity, e.g., leakage of contents of the intragastric balloon, loss of internal volume or pressure, deflation, or damage or other compromise of a component of the intragastric balloon (e.g., the balloon wall, a seam in the balloon, the balloon valve or components associated with the valve structure). The component can be incorporated into the balloon or a component thereof or therein, or can be provided as an additional component added to or affixed to the balloon or a component thereof or therein, or an additional component having a property indicative of failure of the balloon.

In a first aspect, an intragastric balloon is provided, comprising: a device incorporated in the intragastric balloon, the device configured for alerting a patient or caregiver to a failure of the intragastric balloon, wherein the device comprises methylene blue configured to be reduced to leukomethylene blue upon exposure to gastric fluids.

In an embodiment of the first aspect, the failure is spontaneous deflation of the intragastric balloon.

In an embodiment of the first aspect, the failure is leakage of a fill fluid contained within the intragastric balloon.

In an embodiment of the first aspect, the device comprises 10 mg to 60 mg of methylene blue, or 20 mg to 40 mg of methylene blue, or 30 mg of methylene blue.

In an embodiment of the first aspect, the device is methylene blue in liquid form that is injected into the intragastric balloon.

In an embodiment of the first aspect, the device is methylene blue in a solution or suspension in a physiologically acceptable liquid.

In a second aspect, a method is provided for detecting a failure of an intragastric balloon, the method comprising: introducing, into a stomach of a patient, an intragastric balloon comprising a device configured for alerting the patient or a caregiver to a failure of the intragastric balloon, the device comprising methylene blue; introducing an initial fill fluid into a lumen of the intragastric balloon to inflate the intragastric balloon; exposing the inflated intragastric balloon to the in vivo intragastric environment until a failure of the intragastric balloon occurs, whereby the methylene blue is exposed to gastric fluids and is reduced to leukomethylene blue; and detecting a failure of the intragastric balloon, wherein detecting comprises observing a blue green color in the patient's urine upon excretion of leukomethylene blue.

In an embodiment of the second aspect, the failure is spontaneous deflation of the intragastric balloon.

In an embodiment of the second aspect, the failure is leakage of a fill fluid contained within the intragastric balloon.

In an embodiment of the second aspect, the device comprises 10 mg to 60 mg of methylene blue, or 20 mg to 40 mg of methylene blue, or 30 mg of methylene blue.

In an embodiment of the second aspect, the device is methylene blue in a solution or suspension in a physiologically acceptable liquid.

In an embodiment of the second aspect, the device is methylene blue in liquid form that is injected into the intragastric balloon.

In an embodiment of the second aspect, the device is methylene blue in liquid form that is injected into the intragastric balloon separately from the initial fill fluid.

In an embodiment of the second aspect, the device is methylene blue in liquid form that is injected into the intragastric balloon with the initial fill fluid.

In a third aspect, an intragastric device is provided substantially as described in the specification and/or drawings.

In a fourth aspect, a method is provided substantially as described in the specification and/or drawings.

Any of the features of an embodiment of the first through third aspects is applicable to all aspects and embodiments identified herein. Moreover, any of the features of an embodiment of the first through fourth aspects is independently combinable, partly or wholly with other embodiments described herein in any way, e.g., one, two, or three or more embodiments may be combinable in whole or in part. Further, any of the features of an embodiment of the first through fourth aspects may be made optional to other aspects or embodiments. Any aspect or embodiment of a method can be performed by a system or apparatus of another aspect or embodiment, and any aspect or embodiment of a system can be configured to perform a method of another aspect or embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and B are perspective views of an exemplary intragastric volume-occupying device in an inflated state, in accordance with a preferred embodiment.

DETAILED DESCRIPTION

The following description and examples illustrate a preferred embodiment of the present invention in detail. Those of skill in the art will recognize that there are numerous variations and modifications of this invention that are encompassed by its scope. Accordingly, the description of a preferred embodiment should not be deemed to limit the scope of the present invention.

The term “degradable” as used herein is a broad term, and is to be given its ordinary and customary meaning to a person of ordinary skill in the art (and is not to be limited to a special or customized meaning), and refers without limitation to a process by which structural integrity of the balloon is compromised (e.g., by chemical, mechanical, or other means (e.g., light, radiation, heat, etc.) such that deflation occurs. The degradation process can include erosion, dissolution, separation, digestion, disintegration, delamination, comminution, and other such processes. Degradation after a predetermined time, or within a predetermined window of time, after ingestion is particularly preferred.

The term “CO₂ barrier material” as used herein is a broad term, and is to be given its ordinary and customary meaning to a person of ordinary skill in the art (and is not to be limited to a special or customized meaning), and refers without limitation to a material having a permeability to CO₂ of 10 cc/m²/day or less under simulated in vivo conditions (100% humidity and body temperature of 37° C.). As used herein, the term “in vivo conditions” as used herein refers to both actual in vivo conditions, such as in vivo intragastric conditions, and simulated in vivo conditions. The permeability of a material to CO₂ may vary depending upon the conditions under which it is measured.

The term “swallowable” as used herein is a broad term, and is to be given its ordinary and customary meaning to a person of ordinary skill in the art (and is not to be limited to a special or customized meaning), and refers without limitation to ingestion of a balloon by a patient such that the outer capsule and its constituents are delivered to the stomach via normal peristalsis movement. While the systems of preferred embodiments are swallowable, they are also configured by ingestion by methods other than swallowing. The swallowability of the system is derived, at least in part, by the outer container size for the self-inflating system and the catheter and outer container size for the manual inflation system. For the self-inflating system, the outer capsule is sufficient to contain the inner container and its constituents, an amount of activation agent injected prior to administration, the balloon size, and the balloon material thickness. The system is preferably of a size less than the average normal esophagus diameter.

Described herein is a system for an orally ingestible device with one or more failure indicating components. In preferred embodiments, the device is able to traverse the alimentary canal. The device may be useful, for example, as an intragastric volume-occupying device. The device overcomes one or more of the above-described problems and shortcomings found in current intragastric volume-occupying devices. While in certain embodiments specific devices are described, it is understood that the materials and methods can also be applied to other devices.

In order to more clearly describe the subject matter of the preferred embodiments, different embodiments of the same subcomponent will be described under a single relevantly-titled subheading. This organization is not intended to limit the manner in which embodiments of different subcomponents may be combined in accordance with the present invention. The various subcomponents for use in the presently disclosed magnetic, electromagnetic and ultrasonic systems may be discussed under their respective subheaded sections or in any other section, including any section or sections discussing various tracking and visualization subcomponents.

Swallowable Intragastric Balloon System

A swallowable, self-inflating or inflatable intragastric balloon system according to selected preferred embodiments includes the following components: self-sealing valve system for addition of fluid to the lumen of the balloon or to the inner container (“valve system”), a balloon in a deflated and compacted state (“balloon”) and an outer capsule, container, or coating (“outer container”) that contains the balloon. For self-inflating balloons, an inner capsule or other container (“inner container”) that contains one or more CO₂ generating components is present inside the lumen of the balloon. The system may also include various components for facilitating delivery (“delivery components”) of the balloon to the mouth and/or through the esophagus.

For inflatable balloons, an inflation fluid source, a catheter, and tubing (“inflation assembly”) are provided for inflating the balloon after ingestion or placement in the stomach. In the self-inflating balloon configuration, the valve is preferably attached to the inner surface of the balloon by an adhesive or other means (e.g., welding), and provided with an inoculation spacer to prevent puncture of the wall of the balloon and inner container by a needle or other means for injecting an liquid activation agent into the lumen of the balloon via the self-sealing valve. A valve providing releasable attachment of the tubing to the balloon is provided in the inflatable balloon configuration. Preferably, the self-sealing valve system attached to the balloon (e.g., on its inside surface) in the inflatable configuration is “universal” or compatible with a swallowable catheter or a physician-assisted catheter. The valve system serves to allow for balloon inflation using a miniature catheter that includes a needle assembly and also provides a mechanism for detachment of the catheter after inflation has been completed.

The outer container preferably incorporates the balloon in a compacted state (e.g., folded and rolled), preferably with sufficient space to allow for activation liquid to be injected into the balloon in the self-inflating balloon configuration, wherein the liquid activation agent initiates separation, erosion, degradation, and/or dissolution of the inner container and generation of CO₂ upon contact with the inflation agent contained within the inner container, which subsequently causes outer container separation, erosion, degradation, and/or dissolution due to CO₂ gas pressure. In the inflatable balloon configuration, the outer container need only incorporate the balloon in a compacted state.

Selected components of a swallowable intragastric balloon system of a preferred embodiment can include a silicone head with radioopacity ring, trimmed 30 D silicone septum, Nylon 6 inoculation spacer, compacted balloon, inner container (if self-inflating), and outer container as constituents of the system in unassembled form. A fully assembled outer container can include a vent hole aligned with a septum for puncture to inject liquid activation agent (if self-inflating) or a port for connection of tubing (if inflatable). As discussed further below, the components of particularly preferred systems possess the attributes described herein; however, in certain embodiments systems can be employed which utilize components having other attributes and/or values.

Devices according to the preferred embodiments are intended for ingestion by a patient and deployment without the need to resort to invasive methods. It is therefore desirable that the device of the preferred embodiments be operable to conform to a compact delivery state which can be swallowed by a patient with minimal discomfort. Once in the stomach, it is desirable for the device to assume a substantially larger deployed state. In order to achieve the transition from a delivery state to a deployed state the device is subjected to inflation.

Inner Container

In certain embodiments, the balloon is configured to self-inflate. In order to initiate inflation in the self-inflating configuration, a gas generating component is provided which is activated to generate gas. The activation agent is preferably injected using a syringe having a needle with a gauge diameter of from 25 to 32. The needle length is preferably from about 0.25 inches (0.6 cm) to 1 inches (2.54 cm) in length so as to create a flow rate that allows for delivery of the full volume of inflation agent within 30 seconds, but in a manner/stream/flow that does not physically damage the inner container, thereby causing premature CO₂ generation and inflation. The activation agent is preferably pure water, or a solution containing up to 50% concentration of anhydrous citric acid at 20° C., or the equivalent thereof at varying solution temperatures based on solubility of anhydrous citric acid. Preferably, the system is configured to have an occupyable void space in the central lumen of the balloon when in compacted form in the outer container of from about 0.3 ml to about 4.5 ml, such that a corresponding volume of activation agent can be injected into the void space.

In one embodiment, prior to folding, the free-floating inner container with inflation agent for CO₂ generation is preferably vertically aligned with the self-sealing valve system such that the septum/inoculation spacer is placed directly above the tip of the capsule. The balloon contains an inner container. A self-sealing valve system is adhesively adhered to the interior of the wall of the balloon, and the inverted configuration of the balloon is provided by inversion through a hole sealed with a patch. The top approximate ¼ of the balloon wall is folded over the inner capsule, and the pleats where the capsule is are creased similar to the pleats formed in the second step of making a paper airplane, then folded over to the left or to the right. The bottom approximate ¾ of the sphere is then accordioned using no more than 2 creases and folded over the capsule. The left half is then folded over the right half of the capsule or vice versa so that the wings touch. Then the material is rolled over until it creates a tight roll. The device is then placed inside the outer container.

In a self-inflating configuration, the balloon is folded so as to form a pocket around the inner capsule, to insure that the liquid injected through the self-sealing valve system is contained in an area less than 10% of the entire balloon surface area. It is not necessary to provide a pocket in the inflatable configuration, as no inner capsule is provided. The balloon is folded such that the number of total folds is minimized so as to minimize possible damage to the outer material or compromise of barrier properties. The number of total folds is preferably less than 10 folds. The balloon material is rolled when at all possible such that the number of creases required to fit the balloon in an outer container is minimized. This is done in effort to also to prevent lumen material damage. The self-sealing valve is also preferably constructed off-center of the balloon so as to minimize the number of folds that layer on top of each other.

In the self-inflating configuration, the material forming the wall of the balloon is processed and folded to maximize reaction efficiency by localizing the initiation agent injected into the balloon so that it is maintained proximal to the reactants within the inner container. The balloon is folded such that once the reaction initiates and the outer container separates, the balloon unfolds in a manner that creates the largest possible surface area, which prohibits the balloon from readily passing through the pyloric sphincter. The ratio of reactants in the inflation agent and activation agent are selected such that the pH of any remnant liquid inside the lumen of the balloon is acidic, with a pH of less than 6, such that any balloon leakage or breach that allows stomach acid to enter does not cause additional CO₂ generation and resulting unintentional re-inflation.

In a self-inflating configuration, an inflation agent is compressed, formed or otherwise held in a shape which provides good surface area availability for the reactants for CO₂ generation, while minimizing the space and/or volume sufficient to hold the inner container. Preferably, the inner container has a length (longest dimension) of from about 0.748 inches (1.9 cm) to 1.06 inches (2.7 cm) and a diameter or width of from about 0.239 inches (0.6 cm) to about 0.376 inches (1 cm). The volume of the inner container is preferably from about 0.41 ml to about 1.37 ml. The inner container is preferably in the form of a standard push-fit gelatin capsule but a gelatin tape may be used in lieu of a push-fit capsule. The container is preferably relied upon for containing the inflation agent; however, additional sealing or other encapsulation can be employed to control timing of inflation. Gelatin is particularly preferred for use as the inner container; however other materials can also be suitable for use, e.g., cellulose. In order to minimize the internal volume of the system, it is generally preferred to include only a single inner container; however, in certain embodiments two or more internal containers can advantageously be employed. Timing of self-inflation is selected based on a normal esophageal transit time and a normal time of gastric emptying of large food particles, such that the balloon does not inflate to a size that can block the esophageal passageway or prematurely pass through the pyloric sphincter. Timing is also controlled by compacting the balloon such that the activation agent is substantially localized in the balloon next to the inner capsule, creating an efficient CO₂ self-inflation method. Balloon inflation is initiated by the liquid activation agent causing degradation of the inner container, such that the inflation agent in the inner container contacts the liquid activation agent, thereby initiating the gas generation reaction.

The inner container for the self-inflating balloon is contained within the lumen of the balloon and contains the CO₂ generator for balloon self-inflation. The CO₂ generator comprises an inflation agent mixture housed within the container. Preferably, from about 10% to about 80% of the total inflation agent used comprises powdered citric acid, with the remainder comprising powdered sodium bicarbonate. Sufficient inflation agent is provided such that upon completion of the CO₂ generating reaction, the balloon achieves inflation at the nominal inflation pressure described above. Preferably, a total of from about 0.28 to 4 grams inflation agent mixture is employed, depending upon the balloon size to be inflated; preferably up to 1.15 grams of sodium bicarbonate is used with the remainder being powdered citric acid to generate 300 cm³ of CO₂ at nominal pressure.

Outer Container

The balloon is preferably provided in a deflated and folded state in a capsule or other retaining, containing or coating structure (“outer container”), in both the self-inflating and inflation via catheter configurations. The outer container is preferably in the form of a standard push-fit gelatin capsule, with the push-fit relied upon for containing the deflated/folded balloon; however, a gelatin wrap can advantageously be employed in certain embodiments. Gelatin is particularly preferred for use as the outer container; however other materials can also be suitable for use, e.g., cellulose, collagen, and the like. Preferably, the outer container has a length (longest dimension) of from about 0.95 inches (2.4 cm) to 2.5 inches (6.3 cm) and a diameter or width of from about 0.35 inches (0.9 cm) to about 0.9 inches (2.4 cm). The volume of the inner container is preferably from about 1.2 ml to about 8.25 ml. In the self-inflating configuration, the outer container is preferably configured with one or more holes, slits, passageways or other egresses, preferably on each end, which act as vents such that any gas created due to inflation agent exposure to condensation or other ambient moisture present during processing does not cause premature separation or degradation of the inner container prior to 30 seconds after inoculation of the liquid activation agent, which may have an undesirable effect on reaction efficiency. Such egresses can also expedite dissolution of the outer container to prepare the balloon for inflation in the inflatable configuration. The process of the outer capsule degrading (e.g., separates, dissolves, or otherwise opens) is expedited by pressure build up caused by inflation (self-inflation or inflation via catheter) of the balloon. The outer capsule can be dipped in water for a brief time to soften the materials but not release the balloon prior to swallowing to minimize the time lapse between swallowing and balloon inflation. In the inflatable configuration, the outer container is provided with a hole to house the inflation tube needle assembly, wherein the diameter of the catheter needle housing is mechanically compatible with the diameter of the outer container hole such that the needle can be inserted into the self-sealing valve while maintaining therein the housed balloon to facilitate pushing or swallowing of the balloon assembly. In a preferred embodiment, the outer container is a capsule. The distal half of the capsule may be flared to prevent abrasion of the balloon materials by the leading edge of the capsule as the compacted balloon is inserted into the capsule. The capsule can also comprise two parts held together with a gel band and encompassing the folded balloon that allows for quicker separation of the capsule so that inflation can take place more expeditiously. The outer capsule degrades (e.g., separates, dissolves, or otherwise opens) due to contact with ingested fluid ingestion (e.g., water intake) and preferably degrades within 5 minutes or less, more preferably within 2 minutes or less, so as not to cause discomfort to the patient while the balloon/catheter tube is in place.

In a preferred embodiment, the device is fitted into a standard sized gelatin capsule. The capsule may be formed of a material that has a known rate of degradation such that the device will not be released from the capsule or otherwise deployed prior to entry into the stomach. For example, the capsule materials may include one or more polysaccharide and/or one or more polyhydric alcohols.

Alternatively, the device, in its delivery state, may be coated in a substance that confines the device in its delivery state while also facilitating swallowing. The coating may be applied by a dipping, sputtering, vapor deposition, or spraying process which may be conducted at an ambient or positive pressure.

In certain preferred embodiments, the encapsulated or coated device is lubricated or otherwise treated so as to facilitate swallowing. For example, the encapsulated or coated device may be wetted, heated, or cooled, prior to swallowing by the patient. Alternatively, the encapsulated or coated device may be dipped in a viscous substance that will serve to lubricate the device's passage through the esophagus. Examples of possible coatings can be any substances with lubricious and/or hydrophilic properties and include glycerine, polyvinylpyrrolidone (PVP), petroleum jelly, aloe vera, silicon-based materials (e.g. Dow 360) and tetrafluoroethylene (TFE). The coating may also be applied by a sputtering, vapor deposition or spraying process.

In additional embodiments the coating or capsule is impregnated or treated with one or more local anesthetics or analgesics to ease swallowing. Such anesthetics may include anesthetics in the amino amide group, such as articaine, lidocaine and trimecaine, and anesthetics in the amino ester group, such as benzocaine, procaine and tetracaine. Such analgesics may include chloraseptic.

In certain embodiments, the capsule may be weighted at a certain end in order for it to be oriented appropriately when it is administered, as it travels down the esophagus, and/or when it is in the stomach. The weighting components may include polymer materials or inflation reactants.

The swallowable, self-inflating intragastric balloon is provided with mechanisms to reliably control timing of self-inflation such that premature inflation while in the esophagus during swallowing is avoided and sufficient inflation once in the stomach so as to prevent passage through the pyloric sphincter is ensured. Normal esophageal transit time for large food particles has been documented as 4-8 seconds, and gastric emptying of large food particles through the pylorus does not occur for at least 15-20 minutes. The outer container is preferably configured to separate, dissolve, degrade, erode, and/or otherwise allow the deflated/folded balloon to begin unfolding not less than 60 seconds but not more than 15 minutes after inoculation with liquid activation agent. The inner container is preferably configured chemically, mechanically or a combination thereof to retard the initial CO₂ generating chemical reaction such that sufficient CO₂ to begin inflating the balloon is not available earlier than 30 seconds after inoculation with the liquid activation agent, but to permit generation of sufficient CO₂ such that at least 10% of the occupyable volume of the balloon is filled within 30 minutes, at least 60% of the occupyable volume of the balloon is filled within 12 hours, and at least 90% of the occupyable volume of the balloon is filled within 24 hours. This timing allows for injection of the activation agent into the outer container by the medical professional, passing the device to the patient, and swallowing by normal peristaltic means by the patient. This timing also prohibits potential passing of an uninflated balloon into the duodenum by the balloon being inflated to a sufficient size such that gastric emptying of the balloon cannot be easy, as objects more than 7 mm in diameter do not readily pass.

Delivery Components

It certain embodiments, it may advantageous for an administrator of the device to use a delivery tool for delivering the device to the mouth or facilitating its passage through the esophagus in the optimal orientation. A delivery tool may enable the device administrator to inject the device with one or more inflation agents or inflation gases as part of administering the device to the patient. In a preferred embodiment, such injection may be accomplished in the same mechanical action(s) of the administrator that are employed to release the device from the delivery tool into the mouth or esophagus. For example, the delivery tool may include a plunger, a reservoir containing a fluid, and an injection needle. The administrator pushes the plunger which, either in sequence or approximately simultaneously, forces the injection needle into the device and thereby injects the liquid contained in reservoir into the device. Subsequent application of force to the plunger pushes the device out of the delivery tool and into the desired location within the patient. Furthermore, the delivery tool may also include a subcomponent that administers an anesthetic or lubricant into the patient's mouth or esophagus to ease the swallowability of the device.

Balloon

The volume-occupying subcomponent (“balloon”) of the preferred embodiments is generally formed of a flexible material forming a wall which defines an exterior surface and an interior cavity. Various of the above-described subcomponents may be either incorporated into the wall or interior cavity of the volume-occupying subcomponent. The volume-occupying subcomponent can vary in size and shape according to the patient's internal dimensions and the desired outcome. The volume-occupying subcomponent may be engineered to be semi-compliant, allowing the volume-occupying subcomponent to stretch or expand with increases in pressure and/or temperature. Alternatively, in some embodiments, a compliant wall offering little resistance to increases in volume may be desirable.

Spherical volume-occupying subcomponents are preferred in certain embodiments. Alternatively, the volume-occupying subcomponent may be constructed to be donut-shaped, with a hole in the middle of it, and may be weighted and shaped in such a way that it orients in the stomach to cover all or part of the pyloric sphincter, similar to a check valve. The hole in the middle of the volume-occupying subcomponent can then serve as the primary passage for the contents of the stomach to enter the small intestine, limiting the passage of food out of the stomach and inducing satiety by reducing gastric emptying. Volume-occupying subcomponents may be manufactured with different-sized donut-holes according to the degree that gastric emptying is desired to be reduced. Delivery, inflation and deflation of the volume-occupying subcomponent may be accomplished by any of the methods described above.

It is advantageous for the volume-occupying subcomponent wall to be both high in strength and thin, so as to minimize the compacted volume of the device as it travels the esophagus of the patient. In certain embodiments, the volume-occupying subcomponent wall materials are manufactured with a biaxial orientation that imparts a high modulus value to the volume-occupying subcomponent.

In one embodiment, the volume-occupying subcomponent is constructed of a polymeric substance such as polyurethane, polyethylene terephthalate, polyethylene naphthalate, polyvinyl chloride (PVC), Nylon 6, Nylon 12, or polyether block amide (PEBA). The volume-occupying subcomponent may be coated with one or more layers of substances that modify (increase, reduce, or change over time) gas-barrier characteristics, such as a thermoplastic substance.

Preferably, the gas-barrier materials have a low permeability to carbon dioxide or other fluids that may be used to inflate the volume-occupying subcomponent. The barrier layers should have good adherence to the base material. Preferred barrier coating materials include biocompatible poly(hydroxyamino ethers), polyethylene naphthalate, polyvinylidene chloride (PVDC), saran, ethylene vinyl alcohol copolymers, polyvinyl acetate, silicon oxide (SiOx), acrylonitrile copolymers or copolymers of terephthalic acid and isophthalic acid with ethylene glycol and at least one diol. Alternative gas-barrier materials may include polyamine-polyepoxides. These materials are commonly acquired as a solvent or aqueous based thermosetting composition and are generally spray-coated onto a preform and then heat-cured to form the finished barrier coating. Alternative gas-barrier materials which may be applied as coatings to the volume-occupying subcomponent include metals such as silver or aluminum. Other materials that may be used to improve the gas impermeability of the volume-occupying subcomponent include, but are not limited to, gold or any noble metal, PET coated with saran, conformal coatings and the like, as listed, for example, in Tables 1a-b.

In certain preferred embodiments, the volume-occupying subcomponent is injection, blow or rotational molded. Either immediately following such molding, or after a period of curing, the gas-barrier coating may be applied if not already applied within the composite wall.

In another embodiment, the intragastric volume-occupying subcomponent is formed using a Mylar polyester film coating silver, aluminum or kelvalite as a metalized surface, to improve the gas impermeability of the volume-occupying subcomponent.

In the event that the volume-occupying subcomponent's wall is composed of multiple layers of materials, it may be necessary to use certain substances or methods to connect, attach or hold together such multiple layers. Such substances can include a solvent or an ether-based adhesive. Such multiple layers may also be heat-bonded together. Once such layers are attached together to form (for example) a sheet of material to be made into a volume-occupying subcomponent, it may also be necessary to apply additional treatment steps to such material to allow it to seal together (for example, by application of a certain degree of heat and pressure) in order to be made into a volume-occupying subcomponent. Accordingly, it may be advantageous to include as an additional layer in the volume-occupying subcomponent certain materials that seal. For example, a volume-occupying subcomponent comprised of a combination of PET and SiOx layers, which impart favorable mechanical and gas impermeability characteristics to the volume-occupying subcomponent, may be sealed by including a layer of sealable polyethylene in such volume-occupying subcomponent.

According to another embodiment of the preferred embodiments, the functionality of the volume-occupying subcomponent and the deflation component is combined either in part or in whole. For example, the volume-occupying subcomponent may be formed of a substance that is degraded within the stomach over a desired period of time. Once the degradation process has formed a breach in the wall of the volume-occupying subcomponent, the volume-occupying subcomponent deflates, continues to degrade and passes through the remainder of the digestive tract.

Preferably, an automated process is employed that takes a fully constructed volume-occupying subcomponent, evacuates all of the air within the interior cavity and folds or compresses the volume-occupying subcomponent into the desired delivery state. For example, the evacuation of air from the volume-occupying subcomponent may be actuated by vacuum or mechanical pressure (e.g. rolling the volume-occupying subcomponent). In certain embodiments, it is desirable to minimize the number of creases produced in the volume-occupying subcomponent when in the delivery state.

Deflation and/or inflation of the volume-occupying subcomponent may be achieved through one or more injection sites within the wall of the volume-occupying subcomponent. For example, two self-sealing injection sites can be incorporated at opposite sides of the volume-occupying subcomponent. The volume-occupying subcomponent may be positioned within a fixture that employs two small-gauge needles to evacuate the air from the volume-occupying subcomponent.

In one embodiment, the self-sealing injection sites may further be used to insert chemical elements of the inflation subcomponent into the interior of the volume-occupying subcomponent. After injection of the chemical elements into the volume-occupying subcomponent, the same needles may be used to perform evacuation of the volume-occupying subcomponent.

It may be desirable that the volume-occupying subcomponent is packed into the delivery state under, for example, a negative vacuum pressure or under a positive external pressure.

The volume-occupying subcomponent wall materials may also be engineered to, once they are initially punctured or torn, tear relatively easily from the point of such puncture or tear. Such properties can, for example, be advantageous if deflation of the volume-occupying subcomponent were initiated by a tearing or puncturing of the volume-occupying subcomponent wall, since such initial tear or puncture may then increase in scope, hastening and/or maximizing the deflation process.

The volume-occupying subcomponent may also be coated by a lubricious substance that facilitates its passage out of the body following its deflation. Examples of possible coatings can be any substances with lubricious and/or hydrophilic properties and include glycerine, polyvinylpyrrolidone (PVP), petroleum jelly, aloe vera, silicon-based materials (e.g. Dow 360) and tetrafluoroethylene (TFE). The coating may be applied by a dipping, sputtering, vapor deposition or spraying process which may be conducted at an ambient or positive pressure.

The balloon composite wall materials can be of similar construction and composition as those described in U.S. Patent Publication No. 2010-0100116-A1, the contents of which is hereby incorporated by reference in its entirety. The materials are able to contain a fluid, preferably in compressed or non-compressed gas form, such as, e.g., N₂, Ar, O₂, CO₂, or mixture(s) thereof, or atmospheric air (composed of a mixture of N₂, O₂, Ar, CO₂, Ne, CH₄, He, Kr, H₂, and Xe) that simulate gastric space concentrations. In certain embodiments, the balloon is able to hold the fluid (gas) and maintain an acceptable volume for up to 6 months, preferably for at least 1 to 3 months after inflation. Particularly preferred fill gases include non-polar, large molecule gases that can be compressed for delivery.

Prior to placement in the outer container, the balloon is deflated and folded. In the inverted configuration in a deflated state, the balloon is flat, with the inverted seam extending around the perimeter of the balloon. The self-sealing valve system is affixed to the inner wall of the lumen close to the center of the deflated balloon, with the inner container positioned adjacent to the self-sealing valve system. The walls of the balloon are then folded. As part of the balloon design, the self-sealing valve system is manufactured in a manner such that it is placed “off center” to minimize the number of folds upon themselves (e.g., doubling or tripling up) required to fit the balloon in the outer container. For example, the self-sealing valve system can advantageously be placed ½ r±¼ r from the center of the balloon, wherein r is the radius of the balloon along a line extending from the center of the balloon through the septum.

In a preferred embodiment, a self-inflating balloon is fully sealed 360 degrees around. In the self-inflating configuration, with injection of an inflation agent by needle syringe, there are preferably no external openings or orifices to the central lumen. In the inflatable configuration, a valve structure (either protruding, recessed, or flush with the surface of the balloon) is provided for providing an inflation fluid to the central lumen. The balloon can have a “noninverted,” “inverted,” or “overlapped” configuration. In a “noninverted” configuration, the seams or welds and seam allowance, if any, are on the outside of the inflated balloon. In an “overlapped” configuration, layers are overlapped, optionally with one or more folds, and secured to each other via welds, a seam, adhesive, or the like, resulting in a smooth external surface. In an “inverted” configuration, the balloon has a smooth external surface with seams, welds, adhesive bead, or the like inside the inflated balloon. In order to create a balloon with an inverted configuration, e.g., a balloon with no external seam allowance (no wall material between the edge of the balloon and the weld, seam, or other feature joining the sides together), two balloon halves are joined together in some fashion (e.g., adhered using adhesive or heat or the like based on the balloon material used). One of the balloon halves encompasses an opening to allow for the balloon to be pulled through itself after adherence of the two halves and to have the seams of the balloon on the inside. The opening created is preferably circular but can be any similar shape, and the diameter of the opening preferably does not exceed 3.8 cm; however, in certain embodiments a larger diameter may be acceptable. A patch of material is adhered (adhesively, heat welded, or the like, based on the material used) to cover the original balloon-half opening. The inversion hole thus created that is subsequently patched is small enough that the forces exerted during inflation do not compromise the material used to maintain fluid in the balloon.

The preferred shape for the inflated balloon in final assembly is ellipsoid, preferably spheroid or oblate spheroid, with nominal radii of from 1 inch (2.5 cm) to 3 inches (7.6 cm), a nominal height of from 0.25 inches (0.6 cm) to 3 inches (7.6 cm), a volume of from 90 cm³ to 350 cm³ (at 37° C. and at internal nominal pressure and/or full inflation), an internal nominal pressure (at 37° C.) of 0 psi (0 Pa) to 15 psi (103421 Pa), and a weight of less than 15 g. The self-inflating balloon is configured for self-inflation with CO₂ and is configured to retain more than 75% of the original nominal volume for at least 25 days, preferably for at least 90 days when residing in the stomach. The inflatable balloon is configured for inflation with an appropriate mixture of gases so as to deliver a preselected volume profile over a preselected time period (including one or more of volume increase periods, volume decrease periods, or steady state volume periods).

In certain embodiments wherein a stable volume over the useful life of the device is preferred, the balloon is configured to maintain a volume of at least 90% to 110% of its original nominal volume. In other embodiments, it can be desirable for the balloon to increase and/or decrease in volume over its useful life (e.g., in a linear fashion, in a stepwise fashion, or in another non-linear fashion). In other embodiments, the balloon maintains a volume of 75% to 125% of its original nominal volume, or 75% to 150%.

The intragastric device can be a single free-floating or tethered device. In some embodiments, it can be desirable to provide multiple devices (2, 3, 4, 5, 6, or more), either free-floating or tethered to each other, e.g., in a similar configuration to a cluster of grapes. The individual devices can be simultaneously inflated with one inflation system connected to all of the devices, or each device can be provided with a separate inflation system.

Valve System

In preferred embodiments, a self-sealing valve system which contains a self-sealing septum housed within a metallic concentric cylinder is provided. In the inflatable configuration, the self-sealing valve system is preferably adhered to the underside of the balloon material such that only a portion of the valve protrudes slightly outside of the balloon surface to ensure a smooth surface. The valve system for the inflatable configuration can utilize the same self-sealing septum designed for the self-inflating configuration. The septum preferably consists of a material possessing a durometer of 20 Shore A to 60 Shore D. The septum is inserted or otherwise fabricated into the smaller cylinder of the concentric metallic retaining structure that is preferably cylindrical in shape. The smaller cylinder within the larger cylinder controls alignment of the catheter needle sleeve/needle assembly with the septum, provides a hard barrier so that the catheter needle does not pierce the balloon material (needle stop mechanism), and provides compression such that the valve/septum re-seals after inflation and subsequent needle withdrawal.

The concentric valve system can also provide radio opacity during implantation and is preferably titanium, gold, stainless steel, MP35N (nonmagnetic, nickel-cobalt-chromium-molybdenum alloy) or the like. Non-metallic polymeric materials can also be used, e.g., an acrylic, epoxy, polycarbonate, nylon, polyethylene, PEEK, ABS, or PVC or any thermoplastic elastomer or thermoplastic polyurethane that is fabricated to be visible under x-ray (e.g., embedded with barium).

The septum is preferably cone shaped, so that the compressive forces are maximized for self-sealing after inflation. The self-sealing septum allows air to be evacuated from the balloon for processing/compacting and insertion into the outer container, and allows for piercing by an inflation agent syringe needle (self-inflating configuration) or inflation catheter needle (inflatable configuration), and then subsequent withdrawal of the inflation agent syringe needle or detachment of the inflation catheter and withdrawal of the catheter needle significantly limiting gas leakage outside of the balloon during the inflation process and needle withdrawal/catheter detachment. The septum is inserted into the valve using a mechanical fit mechanism to provide compression. An additional ring can be placed at the distal end of the inner cylinder to provide additional compression to ensure the septum material is dense enough to re-seal itself. The ring is preferably metallic in nature, but can also be a non-metallic polymeric material such as an acrylic, epoxy, or thermoplastic elastomer or thermoplastic polyurethane. The ring material is preferably the same material as the cylinder, titanium, but can also be gold, stainless steel, MP35N or the like.

In the inflatable configuration, a larger, outer cylinder of the concentric valve housing contains a slightly harder durometer material than the inner cylinder (50 Shore A or greater), but is also preferably silicone. The purpose of using a harder durometer material is to ensure sealing when connected to the needle sleeve for inflation. The silicone located in the outer ring of the concentric valve is adhered to the balloon from the inside surface. The entire outer cylinder is filled and a small circular lip of this same material is provided that is slightly larger than the diameter of the inner cylinder and extends to the outside surface of the balloon. The lip is compatible with the bell shaped needle sleeve and provides sealing to enhance connection of the valve to the catheter to withstand the inflation pressures applied and also increases the tensile force of the catheter. This silicone lip preferably does not protrude past the balloon surface more than 2 mm to ensure that the balloon surface remains relatively smooth and does not cause abrasion or ulcerations of the mucosa. It is designed to provide compressive forces against the needle sleeve of the catheter for inflation and detachment whereby when connected to the needle sleeve of the inflation catheters, the connection force during the inflation process can withstand up to 35 PSI. The seal is then broken during detachment using hydrostatic pressure that is more than 40 PSI less than 200 PSI to break the connection force. Two additional retaining rings, preferably made of the same material as concentric valve, are included in the valve system to further enhance the seal between the metal and the valve silicone and provide additional mechanical support to ensure proper mechanical fit and are intended to disrupt slippage of the silicone material from the hard (metallic) valve system (causing an increase in tensile force).

The valve structure for the inflatable configuration uses a mechanical fit mechanism to provide the functions of the self-sealable valve for inflation by the catheter and subsequent catheter detachment; however, primer and/or adhesive may be used to provide additional support in maintaining the assembly. The configuration can be modified by modifying the surfaces of the metal components, making them more sticky or slippery to provide the desired mechanical/interference fit. The interference fit between the valve and the catheter can be modified to change the pressure requirements for inflation and/or detachment. Additional assemblies can include overmolding the metallic portions or the concentric system in silicone such that additional support rings to ensure the mechanical fit and the tensile strength and forces required to sustain the assembly during catheter inflation and detachment can be omitted.

The total valve diameter in the inflatable configuration is designed to fit a miniature catheter system that does not exceed 8 French (2.7 mm, 0.105 inches) in diameter. The total diameter does not exceed 1 inch (2.54 cm) and is preferably less than 0.5 inches (1.27 cm), to facilitate swallowing. Additional valves can be added, if desired; however, it is generally preferred to employ a single valve so as to maintain the volume of the deflated/folded balloon (and thus the outer container dimensions) as small as possible. The valve system is preferably attached to the inner surface of the balloon such that a shear force greater than 9 lbs (40 N) is required to dislodge the valve system.

In a self-inflating configuration, the valve system can be attached to the balloon (e.g., on its inside surface) without the use of an opening, orifice, or other conduit in the wall of the balloon. The valve system can utilize a septum with a durometer of 20 Shore A to 60 Shore D. The valve can be inserted or otherwise fabricated into a retaining structure that has a higher durometer, e.g., 40 Shore D to 70 Shore D or more. The retaining structure can be fabricated from a silicone, rubber, soft plastic or any suitable non-metallic polymeric material such as an acrylic, an epoxy, a thermoplastic elastomer, or thermoplastic polyurethane. Preferably, a structure, such as a ring, that can be metallic or non-metallic but radioopaque (e.g., barium) and visible under X-ray, or magnetic or magnetizable and detectable by sensing of a magnetic field, can be embedded in the retaining structure. Using a mechanical fit mechanism of two structures of different durometers, one softer (septum) with a large diameter, can be inserted into a snug, more rigid durometer structure creates compressive forces in the once open orifice to enable CO₂ retention and reduce susceptibility for CO₂ gas leaks. The metallic ring for radio-opacity also helps to create compressive forces on the septum. The self-sealing septum allows air to be evacuated from the balloon for processing/compacting and inserting in the outer container, and also allows for the inflation agent to be injected into the outer container for inflation initiation. Additional septums can be provided, if desired; however, it is generally preferred to employ a single septum so as to maintain the volume of the deflated/folded balloon (and thus the outer capsule) as small as possible. The valve system is preferably attached to the inner surface of the balloon such that a shear force greater than 9 lbs (40 N) is required to dislodge the valve system. A silicone head and opacity ring of a self-sealing valve system can be employed, as can a wedge-shaped septum.

In the self-inflating configuration, an inoculation spacer is preferably incorporated to guide a needle into the self-sealing valve for injection of liquid activation agent into the lumen of the balloon and to prevent the needle from penetrating the wall of the deflated/folded balloon elsewhere such that pressure within the lumen of the balloon cannot be maintained. The inoculation spacer also facilitates preventing liquid activation agent from penetrating the inner container or the folded balloon material, thereby focusing the activation agent in an appropriate manner to properly mix the reactants for CO₂ generation according to the criteria described above. The inoculation spacer is generally in the form of a tube or cylinder. The inoculation spacer is preferably attached to the inner container and/or the self-sealing valve system with an adhesive or other fixing means; however, in certain embodiments the inoculation spacer can be “free-floating” and maintained in position by the folding or rolling of the walls of the balloon. The inoculation spacer can comprise any suitable material that can be passed after separation, erosion, degradation, digestion, and/or dissolution of the outer container; however, preferable materials include non-metallic materials with a minimum Shore D durometer of 40 or more, any metallic material, or a combination thereof. A cupped needle stop (inoculation spacer) can be employed in preferred embodiments.

Inflation Assembly

In certain preferred embodiments, the volume-occupying subcomponent is filled with a fluid using tubing which is subsequently detached and pulled away from the volume-occupying subcomponent. One end of the volume-occupying subcomponent has a port connected to tubing of sufficient length that when unwound can span the entire length of the esophagus, from mouth to stomach. This tubing is connected to the volume-occupying subcomponent with a self-sealable valve or septum that can tear away from the volume-occupying subcomponent and self-seal once the volume-occupying subcomponent is inflated. A physician or other health care professional secures one end of the tubing as the patient swallows the device. Once the device is residing within the stomach, the physician uses the tube to transmit a fluid, such as air, nitrogen, SF₆, other gas(es), vapors, saline solution, pure water, a liquid or vapor under external ambient conditions (e.g., room temperature) that forms a vapor or gas, respectively, at in vivo temperatures (e.g., SF₆), or the like, into the volume-occupying subcomponent and thereby inflate it. The fluid may be or include a variety of other fluid or non-fluid materials as well, including physiologically acceptable fluids, such as aqueous fluids, e.g., water, water with one or more additives (e.g., electrolytes, nutrients, flavorants, colorants, sodium chloride, glucose, etc.), saline solution, or the like. After the volume-occupying subcomponent is fully inflated, the tubing is released and can be pulled out from inside the patient.

The tube may be released in a number of manners. For example, the tubing may be detached by applying a gentle force, or tug, on the tubing. Alternatively, the tubing may be detached by actuating a remote release, such as a magnetic or electronic release. Additionally, the tubing may be released from the volume-occupying subcomponent by an automatic ejection mechanism. Such an ejection mechanism may be actuated by the internal pressure of the inflated volume-occupying subcomponent. For example, the ejection mechanism may be sensitive to a specific pressure beyond which it will open so as to release any excess pressure and simultaneously release the tube. This embodiment provides a desirable feature through combining release of the tubing with a safety valve that serves to avert accidental over inflation of the volume-occupying subcomponent in the patient's stomach.

This automatic release embodiment also provides the benefit that the device inflation step may be more closely monitored and controlled. Current technology allows for a self-inflating intragastric volume-occupying subcomponent which generally begins to inflate in a four minute timeframe after injection with an activation agent such as citric acid. In this approach, the volume-occupying subcomponent may, in some instances, begin to inflate prior to residing within the stomach (e.g., in the esophagus), or, in patients with gastric dumping syndrome or rapid gastric emptying, the volume-occupying subcomponent may end up in the small intestine prior to the time that inflation occurs. Accordingly, in certain embodiments it can be desirable to inflate the volume-occupying subcomponent on command, once it is ascertained that the volume-occupying subcomponent is residing in the correct location.

In certain embodiments, it may also be advantageous for the volume-occupying subcomponent to inflate gradually or in several steps over time, or for the volume-occupying subcomponent to maintain a volume and/or internal pressure within a preselected range. For example, if gas escapes the volume-occupying subcomponent prior to the desired deflation time, it can be beneficial for the device to re-inflate in order to preserve it in its expanded state.

An intragastric balloon system that is manually inflated by a miniature catheter can be employed in certain embodiments. The system preferably remains “swallowable.” The balloon for delivery is in a compacted state and is attached to a flexible, miniature catheter, preferably no larger than 4 French (1.35 mm) in diameter. The catheter is designed such that a portion of the catheter can be bundled or wrapped upon itself for delivery with the encapsulated balloon, allowing the patient to swallow both catheter and balloon for delivery to the stomach. The balloon can contain a self-sealable valve system for attachment of the catheter and inflation of the balloon once it reaches the stomach cavity. The proximal end of the catheter can be left just outside of the patient's mouth, permitting connection to an inflation fluid container that can house the preferred inflation fluid (gas or liquid). After inflation the catheter can be detached from the balloon valve and pulled back through the mouth. This method allows for the intragastric balloon to maintain its swallowability but allow for inflation by a fluid source or a mixture of fluid sources via the catheter. Alternatively, a more rigid, pushable system can be employed wherein the balloon valve is compatible with either the swallowable, flexible catheter or the pushable, rigid catheter assembly.

The inflation catheters (swallowable or administrator-assisted pushable) described herein are configured to deliver the balloon device orally and without any additional tools. The administration procedure does not require conscious sedation or other similar sedation procedures or require endoscopy tools for delivery. However, other versions of the device can be used in conjunction with endoscopy tools for visualization or can be adapted such that the balloon device can be delivered nasogastrically as well.

In operation, the proximal end of the inflation catheter is connected to a valve or connector that allows for connection to the inflation source or the disconnect source, this is preferably a Y-arm connector or inflation valve. The connector materials may consist of polycarbonate or the like and can connect to a single or multi-lumen catheter tube. The distal end of the inflation catheter is connected to the universal balloon valve of the balloon that has been compacted and housed within a gelatin capsule or compacted using gelatin bands. The catheter tube is preferably from 1 French (0.33 mm) to 6 French (2 mm) in diameter. The catheter is preferably long enough to extend out past the mouth (connected to the inflation connector or valve) and transverse the esophagus down to at least the middle of the stomach—approximately 50-60 cm. Measurement ticks can be added to the tubing or catheter to aid in identifying where the end of the tube is located. Timing for inflation can be initiated by having the tube contain a pH sensor that determines a location difference between the esophagus (pH 5-7) and the stomach (pH 1-4) based on the different pH between the two anatomical sources, or can be derived or verified from the expected pressure in a contained (i.e., esophagus) versus a less-constrained space (i.e., stomach). The tube can also contain nitinol that has a tunable transmission to the body temperature, taking into account the timing for swallowing. The tube can also be connected to a series of encapsulated or compacted balloons on a single catheter. Each can be inflated and released separately. The number of balloons released can be tune-able to the patient's needs and desired weight loss. In certain embodiments, the intragastric balloon or catheter is located or tracked in the body by sensing a magnetic field of a magnetizable component of both or either devices, as discussed in detail below.

In certain embodiments, a catheter with the balloon at the distal end (inflated with air) is employed to temporarily and firmly hold the balloon in place. A small deflated balloon catheter can be positioned through the head of the gastric balloon (e.g., a “balloon within the balloon”), and then inflated with air during delivery to firmly hold the capsule and balloon in place and prevent spontaneous detachment of balloon from the catheter. This balloon catheter can incorporate a dual channel that can also allow the bigger gastric balloon to be inflated (by gas or liquid). Once the gastric balloon has been satisfactorily inflated, the small air balloon catheter can be deflated and pulled out of the valve (allowing the valve to self seal), and out of the body, leaving the inflated gastric balloon in the stomach.

In other embodiments, the catheter may be coated to enhance swallowability or is impregnated or treated with one or more local anesthetics or analgesics to ease swallowing. Such anesthetics may include anesthetics in the amino amide group, such as articaine, lidocaine and trimecaine, and anesthetics in the amino ester group, such as benzocaine, procaine and tetracaine. Such analgesics may include chloraseptic.

Dual Lumen Catheter

In a preferred embodiment, a swallowable dual lumen catheter is provided. The dual lumen catheter has two lumens with a diameter of the complete assembly no larger than 5 French (1.67 mm), preferably no larger than 4 French (1.35 mm). The inner lumen preferably does not exceed 3 French (1 mm) and functions as the inflation tube, and the outer lumen preferably does not exceed 5 French (1.67 mm) and functions as the disconnection tube; the inner and outer lumen do not exceed 2 French (0.66 mm) and 4 French (1.35 mm), in diameter, respectively. The catheter assembly is connected to a needle assembly, described in more detail below, at the distal end and to a dual port inflation connector at the proximal end. The tubing that the catheter assembly employs is flexible for swallowability, is kink resistant, can withstand body temperature, is resistant to acid, and is biocompatible as the tube transverses the alimentary canal into the stomach cavity. The tube materials are preferably soft and flexible and have moderate tensile strength and a significant amount of hoop strength to handle applied pressures. The lumens are preferably round and co-axial and free-floating so as to provide flexibility. The dual lumen assembly also preferably requires no adhesive or glue. Alternative lumen configurations can include two D-lumens or a combination of a D-lumen and round lumen, and can be used in stiffer configurations of the final catheter assembly. Preferred materials for the tubing include a thermo-resistant polyethylene tubing such as PEBAX® or a thermo-resistant polyurethane tubing such as PELLETHANE™, PEEK or Nylon. The tubing can also be manufactured out of bioresorbable materials such as polylactic acid (PLA), poly-L-aspartic acid (PLAA), polylactic/glycolic acid (PLG), polycaprolactone (PCL), DL-lactide-co-ϵ-caprolactone (DL-PLCL) or the like, wherein the tube can be released after inflation and detachment and swallowed as normal.

At the distal end of the catheter assembly, the inner lumen or inflation tube is attached to the needle assembly that is used to puncture the balloon's self-sealing valve, preferably located at one of the apexes of the balloon housed inside of a gelatin capsule as outer container. The outer lumen is connected to the needle sleeve and provides connection force between the catheter assembly and balloon providing the tensile strength to withstand balloon inflation pressures, e.g., pressures of up to 10 psi or higher, while maintaining the assembly together. The needle sleeve is configured to mechanically couple with the balloon valve assembly. The needle is preferably made of metal, preferably stainless steel or the like, with a maximum size of 25 gauge (0.455 mm), preferably no smaller than 30 gauge (0.255 mm) for inflation timing purposes. The needle sleeve is preferably a soft material such as nylon or the like, or can also be polycarbonate, polyethylene, PEEK, ABS or PVC. The needle sleeve covers the length of the needle in its entirety, such that the body is protected from the needle and the needle can only pierce the balloon septum. Preferably the needle sleeve is flush or extends out slightly more than the needle length. The needle is inserted into the balloon septum prior to swallowing and maintains a retention force of approximately 0.33 lb (0.15 kg) when coupled to the silicone area of the balloon valve. The needle sleeve is preferably slightly bell shaped or contains a circular relief or lip so that when inserted into the silicone area of the valve a lock and key mechanism is created to increase the tensile strength of the assembly and enhance the sealing for inflation.

At the proximal end, the catheter assembly is connected to a Y-adapter assembly preferably made of polycarbonate. The y-adapter is “keyed” so that the inflation gas and connection fluid are connected to the catheter assembly appropriately and travel down the correct lumen.

Prior to inflation, priming of the disconnection lumen may be employed using a liquid. For example, the outer lumen is first flushed with 2 cc of water, saline, DI water or the like prior to balloon inflation. Thereafter, the inflation source container is attached to the connector leading to the inner lumen. The inflation source container works on the premise of the ideal gas law and a pressure decay model. For a given compressed gas formulation, the device is designed to equalize such that a higher starting pressure is used to inflate the balloon than is the resulting end pressure of the balloon. The starting pressure and volume are dependent upon the gas formulation selected, as well as the length of the catheter and the starting temperature (typically ambient temperature) and ending temperature (typically body temperature).

After inflation, the balloon is detached from the catheter assembly using hydraulic pressure. A syringe filled with water, DI water, or preferably saline is attached to the female end of the Y-assembly. The syringe contains 2 cc of liquid and when the syringe plunger is pushed in, enough hydraulic pressure is exerted such that the needle is ejected from the balloon valve.

Single Lumen Catheter

To further reduce the diameter of the inflation catheter, thereby increasing swallowability comfort, a single lumen catheter can be employed that does not exceed 2 French (0.66 mm) in diameter.

The needle/needle sleeve assembly is similar in design to that of the dual lumen catheter described herein. However, with the single lumen system, the distal end of the catheter lumen connects to the needle sleeve only and there is no second catheter inside. Instead, a single thread attached to a needle hub runs co-axially the length of the catheter to aid in tensile strength for detachment and overall flexibility.

The needle sleeve is slightly bell shaped or contains a circular relief or lip so that when inserted into the silicone area of the valve a lock and key mechanism is created to increase the tensile strength of the assembly, enhance the sealing for inflation, and since this is a single lumen assembly, the lip increases the force required to remove the needle from the valve so this does not occur haphazardly during the inflation process.

The proximal end of the catheter is connected to a 3-way valve and uses a method of exclusion for inflation and detachment of the balloon. The distal end of the catheter contains the needle sleeve, which is made of nylon or other similar source. The needle is metallic and preferably stainless steel.

The tubing that the catheter assembly employs is flexible for swallowability, is kink resistant, can withstand body temperature, is resistant to acid, and is biocompatible as the tube transverses the alimentary canal into the stomach cavity. The tube materials are preferably soft and flexible, preferably co-axial, and resistant to necking or buckling or kinking. For a single lumen system, the catheter tubing is preferably made of PEBAX®, but can also comprise bioresorbable materials such as PLA, PLAA, PLG, PCL, DL-PLCL or the like, wherein the tube can be released after inflation and detachment and swallowed as normal. The wire inside the catheter tubing attached to the needle is preferably a nylon monofilament, but Kevlar or nitinol wire or other suitable materials can also be used.

To inflate the balloon, the distal end of the catheter is attached to the balloon capsule where the needle protrudes through the self-sealable valve. The container is swallowed and a portion of the inflation catheter remains outside of the mouth. The inflation source container is connected to the proximal 3-way valve, where the port for inflation gas is chosen by excluding the other ports. The inflation fluid (preferably compressed nitrogen gas or a mixture of gases) travels down the single catheter lumen, whereby the inflation gas selects the path of least resistance, or more specifically through the needle cavity and into the balloon. The balloon is preferably inflated in less than 3 minutes.

To detach and withdraw the needle from the balloon valve, 2 cc or other suitable volume of water or other liquid is injected into the catheter at a high pressure. Since water has a high surface tension and viscosity, it occludes the needle pathway and the pressure is transferred to the outside needle sleeve, thereby breaking the fit between the needle sleeve and the balloon valve.

If it is desired to place a substance inside the balloon, such as water or acid or any alternative liquid, it can be done by using a lower pressure to inject the liquid.

Miniature Stiff-Bodied Inflation Catheter

In certain embodiments, a stiff-bodied inflation catheter can be employed, which can be placed orally or trans-nasally. This system can be from 1 French (0.33 mm) to 10 French (3.3 mm), preferably 8 French (2.7 mm) in diameter. A larger diameter is typically preferred to enhance pushability, with wall thickness also contributing to pushability and kink resistance. The length of the tube can be approximately 50-60 cm. As discussed above, measurement ticks can be added to the tubing to identify where the end of the tube is located, or a pH or pressure sensor on the catheter can be employed to detect location of the balloon.

This system for inflation/detachment is similar to the dual lumen system described above, but with a larger needle sleeve to accommodate the larger diameter tube. Materials that can be used in the lumen include, e.g., expanded polytetrafluoroethylene (EPTFE) for the outer lumen and polyetheretherketone (PEEK) for the inner lumen. To also enhance pushability, a strain relief device can be added to the distal and proximal ends. It is particularly preferred to have strain relief at the distal end, e.g., 1 to 8 inches, preferably 6 inches, to ensure the catheter bypasses the larynx and follows into the esophagus. The proximal end can have strain relief as well, e.g., to ensure fit of the Y-arm. The preferred material for the strain relief is a polyolefin. The method for inflation/detachment is the same method as for the dual lumen configuration where the outer lumen connects to the needle sleeve and the inner lumen connects to the needle. As part of the procedure, the patient can swallow water or other suitable liquid so as to distend esophageal tissue for smooth passage down of the device. Patients can also be administered an anesthetic at the back of the throat to numb the area and lessen the gag reflex.

The tube can also be connected to a series of encapsulated or compacted balloons on a single catheter such that a total volume of up to 1000 cc or more can be administered, as necessary. Each can be inflated and released separately. The number of balloons released can be tunable to the patient's needs and desired weight loss.

In addition, a catheter can be used for administering a gastric balloon that is similar to balloon catheters used in angioplasty termed “over-the-wire” or rapid exchange catheters. In this case where the patients attempts to swallow the catheter but fails so the stiff catheter—or physician assisted catheter can slide over the flexible catheter and the balloon can be pushed down in the same manner as the physician-assisted catheter. Different materials can be used to provide the varying degrees of flexibility or one material that is fabricated with different diameters across the length to vary the degree of stiffness can be used.

The swallowable self-inflating balloon construction method and the swallowable inflation tube construction method both remove the requirement for endoscopy to place the balloon and make the balloon administration process less invasive. This also allows for the total volume to be placed in a patient to be “titratable,” or adjustable. When a balloon is placed for 30 days, a patient may report that over time they lose their feeling of fullness without eating. To compensate, another balloon can be placed easily without sedation and endoscopy. When a non-deflatable balloon is to be removed endoscopically, it is desirable to color-code the balloon composite walls with different colors so that the physician has a visual marker for removing the balloon at the end of its useful life while keeping the balloon that has remaining useful life in the patient's stomach.

In addition, the balloon wall can be marked approximately 180° from the self-sealing valve such that when the balloon is punctured endoscopically it folds more efficiently on itself so as to facilitate removal of the thin-walled structure without causing esophageal perforations and/or other damage by the balloon due to its shape, stiffness, and/or thickness of the wall material.

Inflation Fluid Container

The inflation fluid container is employed to control the amount or volume of fluid placed inside of the balloon. This can be in the form of a canister of, e.g., PVC, stainless steel, or other suitable material. The container can also be in syringe form. The materials employed are able contain a fluid, preferably in gas form, e.g., compressed or non-compressed N₂, Ar, O₂, CO₂, or mixture(s) thereof, or compressed or non-compressed atmospheric air (a mixture of N₂, O₂, Ar, CO₂, Ne, CH₄, He, Kr, H₂, and Xe). The balloon composite wall materials and respective diffusion gradients and gas permeability characteristics are used to select a fluid for inflation of the intragastric balloon, so as to provide a desired volume profile over time for the inflated balloon. The inflation fluid container materials are selected to ensure no or minimal diffusion or leakage of the fluid before it is connected to the y-arm connector or valve of the inflation catheter. The inflation fluid container preferably incorporates a pressure gauge and a connector. It can also contain a smart chip that notifies the healthcare professional of whether inflation is successful or if the balloon should be detached due to an error in the system.

To maintain “swallowability” of the balloon and to ensure comfort of the patient during the procedure, it is preferred to minimize the amount of time the catheter is placed in the mouth/esophagus. Timing of inflation is can be selected so as to minimize time in place. The outer container-catheter assembly, once swallowed, takes approximately 4-8 seconds to reach the stomach. Once in the stomach, the Inflation source container can be attached to the valve or port of catheter system. Inflation timing can be controlled by selecting the length of catheter, diameter of the catheter tube, the starting temperature, and the starting pressure. Using the Ideal Gas Law for nitrogen and Boyle's Law (P₁V₁=P₂V₂) the amount of starting volume/pressure can be derived, where temperature is controlled inside the inflation source container to match that of the body. It is desired to have an inflation time after swallow of less than 5 minutes, and preferably 2-3 minutes, before balloon detachment and catheter withdrawal. The inputs use to derive inflation of the balloon (preferably in less than 3 minutes) include inflation container volume, type of inflation fluid (preferably a compressed gas or compressed gas mixture), starting pressure, catheter length and diameter, and desired end volume and pressure of the balloon. Thus, due to differences in diameter, a 2 French catheter system requires a higher starting pressure to achieve the same target balloon volume and pressure in the same time frame, assuming use of the same compressed gas formulation. In general, it is understood that starting with a higher pressure with the same flow rate/volume can decrease the inflation time.

The inflation source container provides feedback to the end user based on a pressure decay system. Where there is an expected starting pressure and expected ending pressure to indicate whether the balloon is inflated properly, there is no need for endoscopic visualization. Each scenario of expected pressure outputs can have its own tolerances around it to reduce possibilities of false positives, and the inflation fluid container can provide feedback based on these tolerances as to the status of balloon inflation and detachment. This is derived based on the Ideal Gas Law, where there is an expected end pressure based on the fixed volume of the balloon. If the pressure remains high and doesn't decay as expected, this can indicate a failure in the system (e.g., the balloon container did not dissolve, the balloon is expanding in the esophagus because there is, e.g., a kink in the tube or other failure in the catheter system). For example, for a successful decay using nitrogen only as the inflation fluid, the starting pressure is 22 PSI to inflate a balloon to 250 cc and 1.7 psi (0.120 kg/cm²) for a nylon-based material. To indicate successful balloon inflation, a math chip can be added to the inflation source container that provides at least one of a visual, audible, or tactile notification, or otherwise transmits a notification to a healthcare professional or administrator of whether inflation is successful or if there is an error in the system based on the pressure curve and a set of predetermined pressure tolerances and expected timing of inflation.

Another method for detection of any degree of constraint that the balloon may be experiencing (e.g., capsule dissolved but balloon is in the esophagus or duodenum, or balloon is in the stomach and the capsule has not dissolved by reading the gauge output is to employ an inflation canister that has at least two reservoirs (one large and one small) and at least two gauges, with one or more valves that allow for selection of gas release into the second reservoir or into the balloon itself. With two reservoirs, the larger reservoir can contain the total amount of fluid required to fill the balloon. A small amount of fluid can be released from the larger reservoir into the smaller reservoir first to determine the location of the balloon and its readiness for full inflation. If the small amount of fluid in the smaller reservoir is released into the balloon catheter and the feedback on the gauge of the smaller reservoir indicates that the pressure is high, this indicates that the balloon is still contained in the capsule and it is not ready to be inflated. When the gauge reads back a medium pressure level (e.g., 1-4 psi), this indicates that the balloon is in a constrained space, such as the esophagus or duodenum, and should not be inflated. When the balloon catheter's feedback as read on the gauge is approximately 1 psi, this indicates that the balloon is in the stomach and ready to be inflated. If the feedback is at 0 psi, this indicates is a leak in the balloon valve catheter system and that the device should be retrieved. Once the balloon is detected in the stomach space, then the larger reservoir is opened and the balloon is inflated to its desired pressure.

Alternatively, the balloon can be filled based on a starting pressure by using a spring mechanism, a balloon-within-balloon mechanism, or other pressure source. These mechanisms can potentially result in more predictable/consistent pressure decay curves, and again can have accompanying, predetermined tolerances for feedback back to the end user.

Composite Wall

The materials selected for the composite wall of the balloon may be optimized to maintain the original inflation gas without significant diffusion, or may also allow for diffusion of the gases located in the gastric environment, e.g., CO₂, O₂, argon, or N₂ to diffuse through the wall of the balloon to inflate, partially or wholly, once the balloon is placed in the stomach. A fluid (a liquid or gas) can also be added inside of the balloon using the inflation catheter(s) described herein to change diffusion direction of the balloon composite wall and when it reaches stasis based on the internal and external environment.

A gastric balloon inflated by nitrogen, CO₂ gas, a single fluid (gas) or a mixture of gasses employs a composite wall that provides barrier properties (fluid retention), properties imparting resistance to pH and moisture conditions in the gastric environment or the environment within the central lumen of the balloon, and structural properties to resist gastric motility forces, abrasion of the balloon wall in vivo, and damage during manufacturing and folding of the balloon. Certain materials employed in the balloon materials are able to withstand a hostile gastric environment designed to break down foreign objects (e.g., food particles). Some of the variables that the gastric environment encompasses are as follows: gastric liquid pH of from 1.5-5; temperature of approx. 37° C.; a relative humidity of 90-100%; ingress of gastric space gas content; and constant gastric motility external pressures of from 0-4 psi at variable frequencies and cycle times based on the fed state of the stomach. The external pressure imparted by gastric motility can also cause abrasions on the surface of the balloon. The inside of the balloon lumen may contain moisture from a solution injected in the balloon for timing of auto-deflation or any moisture that has transferred across the membrane due to the external humid environment. In addition to these environmental stresses the wall materials meet biocompatibility requirements and are constructed such that the total thickness of the wall (barrier material) is thin enough to be compacted and placed inside of a swallowable-sized container (“outer container”) without significant damage or lodging. The outer container is small enough to transcend the esophagus (which has a diameter of approximately 2.5 cm). The wall or barrier material is also heat formable and sealable for balloon construct and maintains a bond strength that can contain internal gas pressures of up to 10 psi generated by the initial inflation pressure as well as pressure due to the ingress of gas molecules from the stomach cavity until the system's gas environment reaches stasis. The film properties that are evaluated to determine suitability for use in the composite wall of the balloon include pH resistance, water vapor transmission rate, gas barrier properties, mechanical strength/abrasion properties, temperature resistance, formability, flex-crack (Gelbo) resistance, surface energy (wettability) compliance, and heat bond potential.

The various layers in the composite wall can impart one or more desirable properties to the balloon (e.g., CO₂ retention, resistance to moisture, resistance to acidic environment, wettability for processing, and structural strength). A list of polymer resins and coatings that can be combined into a multi-layer preformed system (“composite wall”) is provided in Tables 1a-b. These films can be adhesively bonded together, co-extruded, or adhered via tie layers or a combination thereof to obtain the desired combination of properties for the composite wall, as discussed below. The materials identified as film coatings in Tables 1a-b are provided as coatings applied to a base polymer film, e.g., PET, Nylon, or other structural layer.

TABLE 1a Film Resins Characteristics Good Structural/ Behavior/ Good Fluid Good Mechanical Retention Manufacturability/ Strength/ Barrier Surface Energy Compliance Properties Properties FILM RESINS Polyethylene X X Terephthalate (PET) Polytrimethylene Terephthalate (PTT) Liquid Crystal X X Polymer (LCP) Polytrimethylene X X naphthalate (PTN) Polyethylene X X naphthalate (PEN) Polyimide (PI) X X Linear Low Density X Polyethylene (LLDPE) Ethylene Vinyl X Alcohol (EVOH) Polyamide: Nylon X X (PA) and Nylon-6 (PAG)/Nylon 12 High Density X Polyethylene (HDPE) Polypropylene (PP) X Polyurethane X PVDC (Saran) X X Polyether Block X Amide (Pebax) Polyvinyl Alcohol X (PVOH) Silicone X X

TABLE 1b Film Coatings Characteristics Good Structural/ Behavior/ Good Fluid Good Mechanical Retention Manufacturability/ Strength/ Barrier Surface Compliance Properties Energy Properties FILM COATINGS Silicon Dioxide X (SiO2) Aluminum Oxide X (Al₂O₃) Nanopolymers X (Nano/Clay) External Organic X Coatings (e.g., epoxy amine) Inorganic Coatings X (e.g., Amorphous Carbon) Oxygen Scavengers X Parylene C X

Fluid Retention Layers

In preferred embodiments, a blended polymer resin using multiple layers is employed to maintain the inflated balloon's shape and volume by retaining the inflation fluid for the duration of the intended use. Certain barrier films, widely used in the food packaging and plastic bottling industries, can advantageously be employed for this purpose in the composite wall of the balloon. Preferably, the barrier materials have a low permeability to carbon dioxide (or other gases, liquids, or fluids that are alternatively or additionally used to inflate the volume-occupying subcomponent). These barrier layers preferably have good adherence to the base material. Preferred barrier coating materials and films include polyethylene terephthalate (PET), linear low density polyethylene (LLDPE), ethylene vinyl alcohol (EVOH), polyamides such as Nylon (PA) and Nylon-6 (PA-6), polyimide (PI), liquid crystal polymer (LCP), high density polyethylene (HDPE), polypropylene (PP), biocompatible poly(hydroxyamino ethers), polyethylene naphthalate, polyvinylidene chloride (PVDC), saran, ethylene vinyl alcohol copolymers, polyvinyl acetate, silicon oxide (SiOx), silicon dioxide (SiO₂), aluminum oxide (Al₂O₃), polyvinyl alcohol (PVOH), nanopolymers (e.g., nanoclay), polyimide thermoset film, EVALCA EVAL EF-XL, Hostaphan GN, Hostaphan RHBY, RHB MI, Techbarrier HX (SiOx-coated PET), Triad Silver (silver metalized PET), Oxyshield 2454, Bicor 84 AOH, acrylonitrile copolymers, and copolymers of terephthalic acid and isophthalic acid with ethylene glycol and at least one diol. Alternative gas-barrier materials include polyamine-polyepoxides. These materials are typically provided as a solvent-based or aqueous-based thermosetting composition and are typically spray-coated onto a preform and then heat-cured to form the finished barrier coating. Alternative gas barrier materials that can be applied as coatings to the volume-occupying subcomponent include metals such as silver or aluminum. Other materials that may be used to improve the gas impermeability of the volume occupying subcomponent include, but are not limited to, gold or any noble metal, PET coated with saran, and conformal coatings.

One method that is used in the packaging industry to delay diffusion of the inflation fluid is to thicken the material. Thickening the material is generally not preferred, as the total composite wall thickness preferably does not exceed 0.004 inches (0.010 cm) in order for the balloon to be foldable into the desired delivery container size for swallowing by a patient.

A multilayer polymer film that is able to withstand the gastric environment over the course of the usable life of the balloon includes linear low density polyethylene (LLDPE) adhesively bonded to a Nylon 12 film. Alternatively, an additional film layer with barrier properties, such as PVDC can be added to the composite wall.

The layers providing gas barrier properties are preferably situated as inner layers in the composite wall as they are less mechanically robust than resins that are considered “structural” such as Nylon and the like.

Structural Layers

Layers such as polyurethane, Nylon, or polyethylene terephthalate (PET) can be added to the composite wall for structural purposes, and are preferably placed as outermost (proximal to the gastric environment or proximal to the central lumen of the balloon) layers, provided that the pH resistance of such layers can withstand the acidic environment of the stomach or the central lumen of the balloon. Other layers may in addition or alternatively be included.

Fabrication of the Composite Wall

The various layers of the composite wall, including the gas barrier layers, need not be situated in any particular order, but those of superior resistance to acidity, temperature, mechanical abrasion, and superior biocompatibility profile are preferably employed as layers contacting the gastric environment. Those with superior resistance to, e.g., acidity and temperature, are preferably employed as layers contacting the central lumen of the balloon.

The various layers of the wall can include a single layer or up to 10 or more different monolayers; however, a film thickness of from 0.001 inches (0.0254 cm) to 0.004 inches (0.010 cm) thick is desirable such that the resulting balloon compacted to fit into a swallowable capsule. The resulting composite wall preferably has good performance specifications with respect to each category listed in Tables 1a-b.

Films that are co-extruded are advantageously employed, as some adhesives may contain leachables that are undesirable from a biocompatibility perspective. In addition, coextrusion allows for better blending such that the materials maintain their original properties when combined in this fashion and are less likely to be subject to delamination when exposed to gastric motility forces.

Combining films with similar properties, e.g., two film layers with excellent gas barrier properties, in a composite wall is advantageous for use in a gastric balloon containing nitrogen, oxygen, CO₂ or a mixture thereof as the inflation gas or where the external environment the product is to be placed in, contains a mixture of gases including CO2, e.g., the stomach. A primary advantage of such composite films is that restrictions on film thickness can be observed without sacrifice of gas barrier properties. Such a configuration also contributes to reducing the effects of processing damage (e.g., manufacturing and compacting) and damage due to exposure to in vivo conditions (e.g., gastric motility forces).

In a particularly preferred embodiment, the composite wall includes a plurality of layers. The first layer is an outer protective layer that is configured for exposure to the gastric environment. This layer is resistant to mechanical forces, exposure to water (vapor), abrasion, and high acidity levels. Nylon or more specifically, Nylon 12 is particularly preferred for the layer exposed to the gastric environment, and is especially resistant to mechanical forces.

In an alternative embodiment, polyurethane is RF welded to saran to yield a 6-7 mil thick composite wall. In another embodiment, a five layer system is provided comprising a layer of saran sandwiched between two polyurethane layers. Between the saran layer and each of the polyurethane layers is a tie layer. The layers can be welded together, co-extruded or adhered using an adhesive. This tri-layer is then co-extruded to Nylon on each side, and then a final sealing layer (polyethylene or the like) is added to one of the nylon layers for the total composite wall. A representative example of material combinations that are commercially available or manufacturable is provided in Table 2. The orientation of the layers (innermost—in contact with the central balloon lumen, or outermost—in contact with the gastric environment) is also indicated if more than two layers are described to support a suggested composite wall.

Most of the film resins listed in Table 2 provide some degree of gas barrier properties. Therefore, many can be used solely to form the balloon wall as a monolayer film; however they can also be used in conjunction with other film resins to meet the desired gas retention and mechanical specifications for the useful life of the balloon based on the inflation gas and external environment the balloon is to be placed in. These film resins can also be coated with gas barrier coatings listed in Tables 1a-b. Additional film layers can be added to form the total composite wall. While such additional layers may not impart substantial barrier properties, they can provide structural and/or mechanical properties, protection for the other layers of the composite wall that are susceptible to water vapor, humidity, pH, or the like, or other desirable properties. The film layers can be assembled using various adhesives, via co-extrusion, via lamination, and/or using tie layers and such to create a composite wall that meets the requirements of an intragastric balloon suitable for use for at least 25 days, or up to 90 days or more, with the specified gas retention properties. Table 2 provides a list of layers and layer combinations suitable for use in composite walls for an intragastric balloon. The composite description, resin abbreviation, configuration (single layer, bilayer, trilayer, or the like) and trade name of commercially available combinations are listed. The number of layers indicated does not include any adhesive layers or tie layers used to fabricate the composite wall, such that a 6-layer composite wall may, for example, have two or three adhesive layers and/or tie layers that make up the total composite wall, and therefore the total number of layers can be eight or nine in final form. The term “layer” as used herein is a broad term, and is to be given its ordinary and customary meaning to a person of ordinary skill in the art (and is not to be limited to a special or customized meaning), and refers without limitation to a single thickness of a homogenous substance (e.g., a coating such as SiOx, or a layer such as PET, or a uniform polymeric blend), as well as to a supporting layer having a coating thereon (wherein a “coating” is, e.g., a material typically employed in conjunction with substrate that provides structural support to the coating layer). For example, a PET-SiOx “layer” is referred to herein, wherein a layer of Si-Ox is provided on a supporting PET layer. In the following table, as well as other tables referring to composite walls, a forward slash (“/”) is used to indicate a boundary between layers of the specified chemistries. The boundary can be a discontinuity, or can be a tie layer, adhesive layer, or other layer separating the layers of recited chemistry.

TABLE 2 Example Film Composite Walls* Abbreviation Trade name polyethylene terephthalate PET Mylar metalized oriented polyethylene metalized OPET Custom terephthalate polyvinyl alcohol coated oriented PVOH coated OPP Bicor polypropylene metalized biaxially oriented nylon metalized OPA6 Custom 6 Biaxally oriented Nylon/ethylene OPA/EVOH/OPA Honeywell vinyl alcohol/biaxially oriented Oxyshield Nylon Plus Nylon/ethylene vinyl alcohol/Low Nylon/EVOH/ Custom Density Polyethylene LDPE polyvinylidene chloride coated PVDC/OPET Mylar oriented polyethylene terephthalate polyvinylidene chloride coated PVCD/OPP Custom oriented polypropylene polyvinylidene chloride coated PVCD/OPA6 Honeywell biaxially oriented Nylon 6 Oxyshield high density polyethylene/ethylene HDPE/EVOH Custom vinyl alcohol polypropylene/ethylene vinyl PP/EVOH Custom alcohol laminate polyethylene PET/EVOH Custom terephthalate/ethylene vinyl alcohol metalized oriented polypropylene metalized OPP Custom sealable PVDC coated oriented PVDC coated PP Custom polypropylene polyvinylidene fluoride PVDF Custom Polyvinyl chloride PVC Custom polyvinyl fluoride PVF Tedlar polychlorofluoroethylene PCTFE ACLAR UltRx, SupRx, Rx amine-based epoxy coated Nylon epoxy coated PA6 Bairocade polyvinyl chloride-polyvinylidene PVC-PVDC Custom chloride copolymer medium density polyethylene MDPE Custom Nylon/Polypropylene Nylon/PP laminate Custom Nylon-High Density Polyethylene Nylon-HDPE Custom laminate Nylon 12/Ethyl Methyl Co-extruded Custom Acrylate/Polyvinylidene Chloride/ Nylon 12- Co-extruded Ethyl Methyl Acrylate/Nylon encapsulated blend 12/Linear Low Density PVDC-Nylon 12- Polyethylene + Low Density LLDPE + LDPE Polyethylene Multi-layer Nylon 12/Linear Low Co-extruded multi- Custom Density Polyethylene + Low layer Nylon 12- Co-Extruded Density Polyethylene LLDPE + LDPE Blend acetylene plasma coating on PET/A Custom polyester difluoroethylene coating on PET/DA Custom polyethylene terephthalate oriented polypropylene OPP Custom cast propylene CPP Custom high density polyethylene HDPE Custom cyclic olefin copolymer COC Custom oriented polystyrene OPS Custom Fluorinated Ethylene Propylene FEP Custom difluoroethylene coating on low LDPE/D Custom density polyethylene difluoroethylene coating on PP/D Custom polypropylene acetylene plasma coating on PP/A Custom polypropylene acetylene plasma coating on low LDPE/A Custom density polyethylene polybutylene terephthalate TPC-ET Hytrel polyether glycol copolymer polyether block amide TPE PEBA Pebax oxide coated biaxially oriented oxide coated PA Honeywell Nylon Oxyshield Ultra Nanoclay/nylon MXD6/Nanoclay Imperm/Aegis OXCE Polyethylene Terephthalate/ PET/SiOx BestPET/ Silicone Dioxide TechBarrier Polyethylene Terephthalate/ PET + 02 MonoxBar Oxygen scavengers Scavengers Modified Polyethylene Modified PET DiamondClear Terephthalate Polyethylene Terephthalate/Nylon PET/MXD6 HP867 6 Amorphous polyvinyl alcohol Amorphous PVOH Nichigo G-Polymer Nylon 6/Ethyl vinyl alcohol/ Nylon 6/EVOH/ Custom Linear Low Density Polyethylene LLDPE Ethyl vinyl alcohol/Poly- EVOH/PP/EVOH Custom Propylene/Ethyl vinyl alcohol Ethyl vinyl alcohol/Nylon EVOH/Nylon Custom Polyethylene/Ethyl vinyl PE/EVOH/PE Custom alcohol/Polyethylene Polyethylene/Ethyl vinyl alcohol/ PE/EVOH/PET Custom Polyethylene Terephthalate Silicon dioxide-coated PET-SiOx/LLDPE/ Custom Polyethylene Terephthalate/Linear EVOH/LLDPE Low Density Polyethylene/Ethyl vinyl alcohol/Linear Low Density Polyethylene Aluminum Oxide-coated PET-Al₂O₃/LLDPE Custom Polyethylene Terephthalate/Polyethylene Polyethylene/Ethyl vinyl PE/EVOH/LLDPE Custom alcohol/Linear Low Density Polyethylene Polyethylene Terephthalate/ PET/PE/OEVOH/ Custom Polyethylene/Polyethylene/ PE Bi-axially oriented Ethyl vinyl alcohol Polyethylene Terephthalate/ PET/PE/EVOH/ Custom Polyethylene/Ethyl vinyl alcohol/ EVOH/EVOH/PE Ethyl vinyl alcohol/Ethyl vinyl alcohol/Polyethylene Polyethylene Terephthalate/ PET/PE/Nylon 6/ Custom Polyethylene/Nylon 6/Ethyl vinyl EVOH/Nylon 6/PE alcohol/Nylon 6/Polyethylene Silicon dioxide-coated PET-SiOx/PE/ Custom Polyethylene Terephthalate/ EVOH/PE Polyethylene/Ethyl vinyl alcohol/ Polyethylene Polyethylene/Ethyl vinyl PE/EVOH/PVDC Custom alcohol/polyvinylchloride Polyethylene Terephthalate/ PET/LLDPE/ Custom Linear Low Density EVOH/LLDPE Polyethylene/Ethyl vinyl alcohol/ Linear Low Density Polyethylene Kurrarister C-coated Polyethylene PET-Kurrarister-C/ Custom Terephthalate/Polyethylene/Ethyl PE/EVOH/PE vinyl alcohol/Polyethylene Polyethylene Terephthalate/ PET/PE/Nylon 6/ Custom Polyethylene/Nylon 6/Ethyl vinyl EVOH/Nylon 6/PE alcohol/Nylon 6/Polyethylene Nylon 6/Ethyl vinyl alcohol/ Nylon 6/ Custom Polyvinylchloride/Low Density EVOH/PVDC/ Polyethylene Nylon 6/LDPE Polyimide PI Custom Polyimide/Linear Low Density PI/LLDPE Custom Polyethylene Polyimide/Polyvinylchloride PI/PVdC Custom Polyimide/Polyvinylchloride/ PI/PVdC/LLDPE Custom Linear Low Density Polyethylene

In particularly preferred embodiments, the composite wall has a thickness of 0.005 inches or less (5.0 mil or less); however, in certain embodiments a thicker composite wall may be acceptable. Generally it is preferred that the composite wall have a thickness of no more than 0.004 inches (4.0 mil). In the descriptions of composite walls in the tables, a designation utilizing forward slashes “/” is employed to indicate a sequence of layers. For example “Polyimide/Polyvinylchloride/Linear Low Density Polyethylene” is used to indicate a sequence of three layers, the layers, in order, being Polyimide, then Polyvinylchloride, then Linear Low Density Polyethylene. No intervening layers or materials can be present, or intervening layers can be present (e.g., tie layers or adhesives).

Confirmation of Deflation of Intragastric Balloon Systems

Whether the balloon is self-deflating or non-self-deflating, various mechanisms may be implemented to confirm leakage or deflation of the balloon, whether planned or unplanned. In preferred embodiments, the balloon deflates and emits a sensory stimulant that is configured to trigger a response by one of the patient's senses. In some embodiments, the device may emit an odor that is smelled by the patient. In some embodiments, the device may emit a taste that is tasted by the patient. In some embodiments, the device may emit a coloring agent that the patient can visually see after passing the agent, for example in a toilet. In some embodiments, the sensory stimulant may cause a physiological response indicative of deflation. For example, the deflated balloon may emit a substance that encourages passage through the bowels.

In some embodiments, flavorants may be used to indicate deflation to the patient. Theses may be the same or different as the flavoring agents that may be used in some embodiments, for example with the ingestible event markers for a voltaic or pH based locating system. Thus, flavorants such as peppermint, oil of wintergreen, cherry flavoring or the like can also be used. Additionally, it may be desirable to add a coloring agent to make the dosage form more attractive in appearance or to help identify the product.

In one embodiment, the intragastric balloon comprises a Proteus® Digital Health Feedback System. It includes an ingestible sensor or sensors. The ingestible sensor is fabricated from food grade materials and is activated upon contact with gastric fluids. The sensor includes no battery and no antenna; instead, it is powered by components in gastric fluids and transmits a unique number generated by the sensor upon activation. Data can be obtained from the sensor using a Bluetooth-enabled device (e.g., a smartphone, tablet, computer, or other similar system), and provide an audible or physical alert (e.g., a tone, vibration, verbal message or the like), or send a message to a caregiver (e.g., an email, a text, a telephone call, a facsimile, or other message format). The Proteus Physiologic Sensing Platform is a technology platform that allows development of products and tools to capture, analyze, and transmit physiologic data about the user. The platform is actively used to develop consumer wellness and medical monitoring devices. The development framework and manufacturing environment support the development of a full range of medical and consumer devices. The platform enables the development of products that: Capture Real Time Physiologic Data; Process and Store Captured Data; Wirelessly Transmit Data; Monitor and Set Alerts; Are Comfortable to Wear; and Are Very Low Cost. The sensor can be inserted into the balloon and be allowed to move freely within the balloon. Alternatively, it can be attached to an inner wall of the balloon. The sensor may be incorporated in a the balloon in an unencapsulated form as received from the manufacturer, or can be provided with a suitable aqueous or gastric-fluid soluble encapsulation, e.g., a gelatin coating or polysaccharide coating, or it can be enclosed in an envelope or other coating comprising a material with a resistance to moisture or water having a pH close to neutral, but minimal resistance to acidic gastric fluid. The latter embodiment can be desirable in certain intragastric balloons having a degree of permeability to water, wherein over time water vapor/moisture can accumulate in the interior of an intact balloon, to offer protection to the sensor prior to its activation by acidic gastric fluids.

Biomarkers can be utilized in connection with the intragastric device in certain embodiments to detect failure of the device. The terms “biomarker” or “biological marker” refer to a broad subcategory of medical signs—that is, objective indications of medical state observed from outside the patient—which can be measured accurately and reproducibly. Biomarkers can include almost any measurement reflecting an interaction between a biological system and a potential hazard, which may be chemical, physical, or biological. The measured response may be functional and physiological, biochemical at the cellular level, or a molecular interaction.” Examples of biomarkers include everything from pulse and blood pressure through basic chemistries to more complex laboratory tests of blood and other tissues. Medical signs have a long history of use in clinical practice and biomarkers are the most objective, quantifiable medical signs modern laboratory science allows to be measured reproducibly. In one embodiment, the intragastric system incorporates a substance in its interior that provokes a physiological process in a patient, and the result of that process is a detected biomarker indicating failure of the device. For example, the intragastric device can contain a substance, e.g., a harmless virus or bacteria or component thereof that triggers antibody production. Detection of the antibody indicates device failure (e.g., a leak or deflation permitting escape of the substance). The balloon could also incorporate a drug or other chemical that induces a physiological change, e.g., adrenaline inducing a rapid heart rate, ethanol that produces ethyl glucuronide upon release into the body where it is metabolized, or the like. The biomarker can be detected using a suitable detection device. For example, if a rapid heart rate, elevated skin temperature, or perspiration is the biomarker, a wearable device, e.g., an activity tracker such as a FitBit or similar device can be employed. Alternatively, in the case of a metabolic product in a body fluid (blood, urine), a colorimetric or electrochemical test strip can be employed. Other sensors are known for use in connection with breath or perspiration. Other substances can be used that induce a physical symptom as a biomarker, e.g., for example, laxatives (e.g., phenolphthalein) and emetics (e.g., apomorphine, xylazine, hydrogen peroxide).

In embodiments wherein it is desirable to alert the patient directly to failure of the device, tracer compounds can be advantageously employed. These can fall into one or more general categories in terms of the alerting effect: smell/odor, taste/flavor, or visual. For smell as an alerting effect, a small amount of mercaptan gas can be incorporated in the balloon's fill gas. Such substances, when released, will emit a foul odor, e.g., in a burp or other release of gases from the gastrointestinal system, but be otherwise physiological inactive. Suitable substances include methyl mercaptan, benzyl mercaptan, butyl mercaptan, ethyl mercaptan, skatole, butyric acid, butyric anhydride, cadaverine, putrescine, or the like. Such substances are advantageously of an aroma not normally encountered in connection with food, beverages, or normal bodily functions. Desirably, such substances are detectable at very low levels (e.g., parts per billion by weight) and are either gaseous or volatile. Substances that can produce a detectible taste include vanillyl butyl ether, allyl isothiocyanate, piperine, capsaicin, allicin, or diallyl disulfide. Other flavorants include diacetyl, isoamyl acetate, benzaldehyde, cinnamaldehyde, ethyl propionate, methyl anthranilate, limonene, ethyl decadienoate, allyl hexanoate, ethyl maltol, ethylvanillin, and methyl salicylate. Bitterants can advantageously be employed, such as denatonium, sucrose octaacetate, quercetin, brucine, or quassin. In terms of visual indicators, substances that can produce a color in urine can advantageously be employed. The active ingredients in vitamins or certain foods (such as asparagus) that cause urine odor can be incorporated as a tracer, as can certain supplements (e.g., fish oils). Alternatively, substances that are otherwise detectable in urine can be employed. Examples of substances for detection by visual or other analysis of urine include, for example, betacyanin (red food coloring), indican (precursor to indigo blue), indigo carmine (used in urologic surgery), riboflavin vitamin B2 (bright yellow), methylene blue (used as a placebo in pills), trypan blue, congo red, brilliant blue, Eosin Y, Erythrosine B, Fast Green FCF, iodine, safranin, triamterene, amtrip, cascara chloroquine ferrous salts, dextran, levodopa, methocarbamol, methyldopa, metronidazole, nitrates, nitrofurantoin, quinine, sulfonamides, bismuth, chloroquine, primaquine, senna, amitriptyline, chlorzoxazone, dihydroergotamine, heparin, phenazopyridine, rifampin, sulfasalazine, warfarin, daunorubicin, doxorubicin, ibuprophen, methyldopa, phenothiazines, phenytoin, phenylbutazone, rifampin, salicylates, and the like. For detection in feces, heptamethine dyes or dyes detectable upon contact with near-IR light are desirable. In some embodiments, the substance produces a color detectable by the unaided human eye, e.g., in the range of visually detectable frequencies. Alternatively, the substance can produce a color outside of this frequency range, e.g., detectable by application of ultraviolet light, or that are naturally fluorescent. Substances that can impart a sensation upon urination or defecation can also be employed, e.g., capsaicin or other such substances that impart a burning sensation.

When a tracer is employed in the intragastric balloon, it can be incorporated in any suitable form. Gas tracers can be added to the fill gas mixture. Liquids can be injected in liquid form into the balloon. Solids can be provided as pellets, powders, e.g., pulverized solids or lyophilized powers, or the like.

The device can incorporate a radio-frequency identification (RFID) device. Such devices use of electromagnetic fields to transfer data, for the purposes of automatically identifying and tracking tags attached to or included/imbedded within objects. The tags contain electronically stored information. Some tags are powered by electromagnetic induction from magnetic fields produced near the reader. Some types collect energy from the interrogating radio waves and act as a passive transponder. In preferred embodiments, the RFID tag is a passive tag that is used in conjunction with an active reader. The intragastric balloon can incorporate a passive RFID tag on one side of the balloon and a counterweight on the other. For a balloon in an inflated state, the RFID tag will be positioned at the top of the stomach. Upon deflation, the RFID tag will be expected to fall to the bottom of the stomach. By calibrating the location of the tag upon initial inflation, detection of the RFID tag at a lower position suggests deflation. Alternatively, instead of a counterweight, a second RFID tag can be incorporated on an opposite side of the balloon. Detection of the RFID tags in a spaced apart configuration can suggest that the balloon is inflated, while a close spacing can indicate possible deflation.

In another embodiment, magnets are secured on opposite sides of the balloon. In an inflated state, the magnets will be spaced apart. Upon deflation, the magnets can be held in proximity to each other by their magnetic fields. By detecting the change in magnetic characteristics for the spaced apart versus paired configuration, deflation can be detected. Similarly, a wire or other conductive trace can be incorporated in the balloon wall. Deflection of the wire can be detected by a strain gauge, or other sensor, suggesting deflation of the device.

For example, in embodiments employing multiple agents or chemical components which react with one another to inflate the volume-occupying subcomponent, the proportions and amounts of each agent may be manipulated such that the inflation reaction stops prior to exhaustion of all of one of the agents. The remaining quantity of agent will thereby function as a weight in the volume-occupying subcomponent. Alternatively, various other elements of the inflation subcomponent may be designed to ultimately serve as a weight, e.g. the capsule or other retaining element that otherwise serves to separate the reactive agents may also provide a weighting function after inflation. Alternatively, one or more solids or liquids produced as reaction byproducts may serve to weigh or orient the volume-occupying subcomponent. As illustrated in FIGS. 1A and B, the volume-occupying subcomponent 400 encloses a solid component in pellet form 132, the component being soluble in gastric fluid. Upon loss of structural integrity of the volume-occupying subcomponent 400, gastric fluids can enter and exit the balloon, solubilizing the component and permitting it to enter the gastric space.

Amounts of dyes as discussed herein providing a suitable effect in an intragastric balloon can be as low as 10 mg or less; however, higher amounts can also be employed, e.g., 15 mg, 20 mg, 25 mg, 30, mg, 35 mg, 40 mg, 45 mg, 50 mg, 55 mg, 60 mg, 65 mg, 70 mg, 75 mg, 80 mg, 85 mg, 90 mg, 95 mg, or 150 mg, 100 mg, 200 mg, or higher. An amount of from about 15 mg to about 60 mg is typically employed, e.g., about 20-40 mg, e.g., about 30 mg. Similar amounts can also be employed for the other dyes identified herein. The dye can be injected into the balloon in a liquid form, e.g., a pure liquid or, e.g., a solution, emulsion, or suspension in a suitable liquid, e.g., water, ethanol, mineral oil, vegetable oil, or any other physiological acceptable liquid or combination thereof, alone or in combination with other pharmaceutically acceptable excipients, e.g., components to assist in solubilizing or forming a stable emulsion or suspension of the dye. Alternatively, or additionally, it can be provided in a solid form, e.g., a paste, a pellet, granules, powder, encapsulated form, or any other suitable form, either in a pure state or in combination with other pharmaceutically acceptable excipients. The dye can be placed in the balloon at the time of manufacture, e.g., a pellet or powder of the dye is placed in the balloon, or a coating of the dye is applied to an interior wall or other structure in the balloon. Alternatively, the dye can be placed in the balloon by a physician or other individual administrating the balloon to a patient after manufacture, e.g., prior to, concurrent with, or after inflation in vivo.

The amounts and liquid or solid forms of other types of components (e.g., flavorants, dyes, odor generating compounds, physiological effect inducing compounds, biomarkers, etc.) and methods for incorporating into the balloon are the same as or similar to those described above for dyes.

If the indicator component is in a gaseous form, it can be placed in the balloon during manufacturing by injection into the balloon, e.g., through a self sealing valve, or by assembling the balloon in an atmosphere comprising the gas. Alternatively, the indicator component can be placed in the balloon by a physician or other individual administrating the balloon to a patient after manufacture, e.g., prior to, concurrent with, or after inflation in vivo, e.g., as a component of the initial fill gas, or as a component to the fill gas added separately. Gaseous components typically can be employed so as to provide from 0.1 ppb (parts per billion on a weight basis) or less to 1000 ppb or more of the initial fill gas, e.g., 0.1-500 ppb, 0.1-400 ppb, 0.1-300 ppb, 0.1-200 ppb, 0.1-200 ppb, 0.1-100 ppb, 0.1-50 ppb, or 0.1-10 ppb.

Fabrication of the Balloon

To ensure good mechanical strength of the balloon, the balloon is preferably thermoformed and sealed such that the edges of the pieces used to form the balloon are overlapping. This can be accomplished by any suitable method. For example, two flat sheets of material can be placed in a frame with magnetized edges to hold the two sheets in place. Slack can be added to the piece of film to orient the material such that it maintains its properties after the thermoforming process. The frame can be placed over a mold that represents a hemisphere the balloon. A heater (e.g., a 4520 watt infrared heater) can be used to form the material, and a vacuum can be pulled. The material, with slack put in it prior to vacuum being applied, re-orients the material such that it is more evenly distributed around the hemisphere shape. The material is preferably thickest in the middle and is made thinner on the sides where it will be welded to a second piece to create a sphere or ellipsoid having a substantially uniform wall thickness. For example, starting with a 0.0295″ film, the middle of the film or subsequent apex has an ending film thickness of 0.0045″ and the edges have an ending thickness of 0.0265″ for subsequent overlapping during the welding process.

The valve can be adhered to the (e.g., polyethylene, PE) side of one of the hemispheres and protrude out of the opposite (e.g., nylon) side. One hemisphere typically consists of Nylon as the outermost layer and the second hemisphere typically has polyethylene (sealing web) as the outermost layer. The edges of the two hemispheres are preferably aligned such that they overlap by at least 1 mm and no more than 5 mm. Alignment and overlay of the two hemispheres is done to compensate for the thinning at the edges during the thermoforming process, which in turn inhibits seam bursts in vivo. Each half of the spheroid is placed on a fixture and the excess from the thermoforming process is trimmed. On a multi-layer film, the sealing layer, a PE or similar layer is bonded to the sealing layer of the second film half. To do this the film of the hemisphere that has the nylon exposed to the external environment is folded up along the edges of the sphere on one half such that it can be bonded to the hemisphere with the polyethylene on the outermost layer.

The two film pieces are then sealed using a roller bonder or a band heater. In the roller bonder, the air provides the compression, the heater provides the sealing heat, and a motor that moves the bonder around the area controls the time that is required to ensure proper sealing. In the band heater, there is a heating element, an expandable plug that provides the compression, and a timer. The band is a metal, preferably copper and a spool-like fixture provides the compression needed. Using film layers of different melt temperatures helps ensure integrity of the barrier layers of the final balloon configuration. If two similar materials are welded, then an insulator can be employed. In a preferred embodiment, one sphere is provided with the Nylon layer facing out and the second sphere has a PE layer facing out.

Balloons with Resistance to Spontaneous Deflation

The largest percentage of intragastric balloon malfunctions is due to spontaneous deflations. Spontaneous deflations can occur due to (1) external puncture of the intragastric balloon due to gastric motility forces, (2) over inflation of the balloon due to increased internal pressure of the balloon from uptake of the gastric environment of the gasses and water vapor and (3) under inflation of the balloon that leads to fatiguing of the excess material and subsequent puncture of the balloon. By managing these two variables and tuning these variables to withstand the dynamic gastric environment, the balloon system can be tailored to ensure it remains inflated throughout its useful life. Instances of spontaneous deflation in this intragastric balloon can be minimized by selection of the starting inflation gas in conjunction with selection of the composite wall materials and construction. Selection of the permeability characteristics with respect to water vapor transmission and gas permeability of the composite wall so as to take advantage of the properties of the gastric space contents can enable the rate of diffusion of gases into and out of the balloon to be controlled. This method allows for a tunable method for prevention of under inflation and over inflation.

Another phenomenon seen with gastric balloons and obesity in general is stomach accommodation. In the process of stomach accommodation, the stomach grows to accommodate the space occupying device or excess food that is ingested. In the process of stomach accommodation, the volume of a stomach containing an intragastric balloon grows over time, such that the patient becomes hungrier. However, by controlling gas diffusion and water vapor transmission across the balloon wall over time, the balloon size can also be increased over time by selecting the starting inflation gas(es) and water and other in vivo gas permeability characteristics of the film so as to maintain weight loss. In addition to spontaneous deflations, selecting the permeability characteristics of the composite wall in conjunction with the starting gases and utilizing the transfer of gases and water inside of the balloon from the gastric environment, the balloon can be designed to grow over its useful life in response to stomach accommodation.

Experiments were performed wherein various starting inflation gases were selected in conjunction with varying external gas environments that mimic the stomach gas and water environment in vivo. The stomach environment consists of water, acid (hydrochloric acid), a mixture of gases, and chyme (the semifluid mass of partly digested food expelled by the stomach into the duodenum). Stomach gas usually arises from swallowing air during eating. The composition of air is nitrogen (N₂) 78.084%; oxygen (O₂) 20.9476%; argon (Ar) 0.934%; carbon dioxide (CO₂) 0.0314%; neon (Ne) 0.001818%; methane (CH₄) 0.0002%; helium (He) 0.000524%; krypton (Kr) 0.000114%; hydrogen (H₂) 0.00005%; and xenon (Xe) 0.0000087%.

Five gases constitute greater than 99% of the gases in gastrointestinal system: N₂, O₂, CO₂, H₂ and methane, with nitrogen predominating. Gastric pCO₂ closely parallels local (splanchnic) arterial and draining venous blood pCO₂ values. Neutralization of stomach acid can also generate gas. For example, when the stomach acid reacts with bicarbonates (e.g., as are present in certain antacids) in the digestive juices, the chemical process creates CO₂, which is normally absorbed into the blood stream. Digestion of food in the intestines, mainly through fermentation by colonic bacteria, generates CO₂, H₂, and methane. Microbes appear to be the sole source of all of the hydrogen and methane produced in the intestine. These arise from fermentation and digestion of nutrients (polysaccharides from fruits and vegetables are not digested in the small intestines). Small quantities of a few other gases, including hydrogen sulfide, indoles, and ammonia can also be generated.

In certain embodiments, the composition of the initial fill gas is substantially characteristic of the composition of the mixture of gases in the in vivo gastric environment, or comprises components found in gases in the in vivo gastric environment. Such an initial fill gas can include only N₂ and CO₂, or can include only N₂, CO₂, and O₂, or can include N₂ and CO₂ as well as one or more other gases present in the in vivo environment (e.g., water vapor, H₂, CH₄, Ar, H₂S, or NH₃). Argon or another inert gas (or inert gases) can be substituted in part or in whole for N₂, which is considered an inert gas in the context of the preferred embodiments. In those embodiments wherein the fill gas includes only N₂ or CO₂, it is preferred that the initial fill gas comprises from about 75% v/v to about 96% v/v N₂, from about 5% v/v to about 15% (vol.) O₂, and from about 1% v/v to about 10% v/v CO₂, more preferably from about 80% (vol.) to about 85% (vol.) N₂, from about 5% (vol.) to about 13% (vol.) 0₂, and from about 4% (vol.) to about 8% (vol.) CO₂. In those embodiments wherein the fill gas includes only N₂ or CO₂, it is preferred that the initial fill gas comprises from about 4% (vol.) to about 8% (vol.) CO₂, with the remainder N₂ or another inert gas. In embodiments wherein the initial fill gas comprises other gases in addition to CO₂ and the inert gas(es), it is preferred that the initial fill gas comprises from about 4% (vol.) to about 8% (vol.) CO₂. Examples of inert gases include but are not limited to nitrogen, as well as argon, SF₆, C₂F₆, C₃F₈, C₄F₁₀, C₄F₈, C₄F₈, C₃F₆, CF₄, and CClF₂-CF₃.

An inert gas in conjunction with a less inert gas(es) that is more soluble in the gastric environment, can be combined to comprise the starting balloon inflation gas composition where the inert gas would be in excess to the more soluble/diffusible gas. In certain embodiments, it is preferred to combine nitrogen as a more soluble/diffusible gas with a gas of lower diffusivity/solubility such as SF₆, C₂F₆, C₃F₈, C₄F₁₀, C₄F₈, C₄F₈, C₃F₆, CF₄, and CClF₂-CF₃. For example, a fill gas of certain embodiments can comprise 5% (vol.) of the more soluble/diffusible inert gas in combination with 95% (vol.) of the less soluble/diffusible inert gas (e.g., 5% N₂ in combination with 95% SF₆); or 10% of the more soluble/diffusible inert gas in combination with 90% of the less soluble/diffusible inert gas (e.g., 10% N₂ in combination with 90% SF₆); or 15% of the more soluble/diffusible inert gas in combination with 85% of the less soluble/diffusible inert gas (e.g., 15% N₂ in combination with 85% SF₆); or 20% of the more soluble/diffusible inert gas in combination with 80% of the less soluble/diffusible inert gas (e.g., 20% N₂ in combination with 80% SF₆); or 25% of the more soluble/diffusible inert gas in combination with 75% of the less soluble/diffusible inert gas (e.g., 25% N₂ in combination with 75% SF₆); or 30% of the more soluble/diffusible inert gas in combination with 70% of the less soluble/diffusible inert gas (e.g., 30% N₂ in combination with 70% SF₆); or 35% of the more soluble/diffusible inert gas in combination with 65% of the less soluble/diffusible inert gas (e.g., 35% N₂ in combination with 65% SF₆); or 40% of the more soluble/diffusible inert gas in combination with 60% of the less soluble/diffusible inert gas (e.g., 40% N₂ in combination with 60% SF₆); or 45% of the more soluble/diffusible inert gas in combination with 55% of the less soluble/diffusible inert gas (e.g., 45% N₂ in combination with 55% SF₆); or 50% of the more soluble/diffusible inert gas in combination with 50% of the less soluble/diffusible inert gas (e.g., 50% N₂ in combination with 50% SF₆). In certain embodiments, an initial fill gas consisting of 20% of the less soluble/diffusible inert gas with the remainder a more soluble/diffusible inert gas is employed; or an initial fill gas consisting of 19-21% of the less soluble/diffusible inert gas with the remainder a more soluble/diffusible inert gas is employed; or an initial fill gas consisting of 18-22% of the less soluble/diffusible inert gas with the remainder a more soluble/diffusible inert gas is employed; or an initial fill gas consisting of 17-23% of the less soluble/diffusible inert gas with the remainder a more soluble/diffusible inert gas is employed; or an initial fill gas consisting of 16-24% of the less soluble/diffusible inert gas with the remainder a more soluble/diffusible inert gas is employed; or an initial fill gas consisting of 15-25% of the less soluble/diffusible inert gas with the remainder a more soluble/diffusible inert gas is employed. For example, an initial fill gas comprising 18-20% SF₆ with the remainder as nitrogen can be employed, or 19-21% SF₆ with the remainder as nitrogen; or 18-22% SF₆ with the remainder as nitrogen; or 17-23% SF₆ with the remainder as nitrogen; or 16-24% SF₆ with the remainder as nitrogen; or 15-25% SF₆ with the remainder as nitrogen. In some embodiments, the initial fill gas comprises liquid SF₆ or other perflorocarbon in liquid form, which equilibrates in vivo to mixture of liquid and vapor.

Controlled self-inflation of the intragastric balloon in the in vivo environment can be achieved by using a semi-permeable or permeable composite wall in the balloon and initially filling the balloon with a preselected single gas, such as N₂ or O₂. The balloon utilizes differences in concentrations of gases and water concentration differences between the internal balloon environment and the external environment in vivo (GI/stomach) to increase and/or decrease the volume and/or pressure over time. To achieve a controlled decrease in volume and/or pressure, a wall can be employed that has a relatively higher permeability to the single gas used to inflate the balloon than to other gases present in the in vivo gastrointestinal environment. For example, if nitrogen gas is employed as the inflation gas, over time in the in vivo environment, the volume and/or pressure in the balloon will decrease as nitrogen diffuses out into the in vivo environment through the oxygen permeable wall. Similarly, if oxygen gas is employed as the inflation gas, over time in the in vivo environment, the volume and/or pressure in the balloon will decrease as oxygen diffuses out into the in vivo environment through the oxygen permeable wall. The differential in partial pressure of the single gas in the balloon (higher) versus the in vivo environment (lower) will drive the process until equilibrium or homeostasis is reached. To achieve a controlled increase in volume and/or pressure, a wall can be employed that has a relatively lower permeability to the single gas used to inflate the balloon than to other gases present in the in vivo gastrointestinal environment. For example, if nitrogen gas is employed as the inflation gas, over time in the in vivo environment, the volume and/or pressure in the balloon will increase as CO₂, and all of the other gases present in the gastric environment, diffuse into the balloon through the CO₂ permeable wall. The differential in partial pressure of the permeable gas in the balloon (lower) versus the in vivo environment (higher) will drive the process until equilibrium is reached.

In addition, maintaining and/or controlling inflation of the balloon can also be done using the differences in concentrations between the internal balloon environment and external gastric environment in which the balloon volume/pressure can be increased or decreased as needed to extend the useful life of the product. One reason to decrease the pressure can be to first inflate the balloon with a large, but highly diffusible/soluble gas molecule such as CO₂ in addition to a more inert gas like nitrogen to pre-stretch the balloon, with the soluble gas diffusing out of the balloon and other gases not originally present in the balloon migrating in to fill the balloon.

Inflation gases can be selected to start with the majority of the gas in the balloon comprising a large, inert gas or a gas that has low diffusivity through the selected composite wall. Examples of inert gases include but are not limited to nitrogen, as well as SF₆, C₂F₆, C₃F₈, C₄F₁₀ C₄F₈, C₄F₈, C₃F₆, CF₄, and CClF₂-CF₃. An inert gas in conjunction with a less inert gas(es) that are more soluble in the gastric environment, can be combined to comprise the starting balloon inflation gas composition where the inert gas would be in excess to the more soluble/diffusible gas. In certain embodiments, it is preferred to combine nitrogen as a more soluble/diffusible gas with a gas of lower diffusivity/solubility such as SF₆, C₂F₆, C₃F₈, C₄F₁₀, C₄F₈, C₄F₈, C₃F₆, CF₄, and CClF₂-CF₃. For example, a fill gas of certain embodiments can comprise 5% (vol.) of the more soluble/diffusible inert gas in combination with 95% (vol.) of the less soluble/diffusible inert gas (e.g., 5% N₂ in combination with 95% SF₆); or 10% of the more soluble/diffusible inert gas in combination with 90% of the less soluble/diffusible inert gas (e.g., 10% N₂ in combination with 90% SF₆); or 15% of the more soluble/diffusible inert gas in combination with 85% of the less soluble/diffusible inert gas (e.g., 15% N₂ in combination with 85% SF₆); or 20% of the more soluble/diffusible inert gas in combination with 80% of the less soluble/diffusible inert gas (e.g., 20% N₂ in combination with 80% SF₆); or 25% of the more soluble/diffusible inert gas in combination with 75% of the less soluble/diffusible inert gas (e.g., 25% N₂ in combination with 75% SF₆); or 30% of the more soluble/diffusible inert gas in combination with 70% of the less soluble/diffusible inert gas (e.g., 30% N₂ in combination with 70% SF₆); or 35% of the more soluble/diffusible inert gas in combination with 65% of the less soluble/diffusible inert gas (e.g., 35% N₂ in combination with 65% SF₆); or 40% of the more soluble/diffusible inert gas in combination with 60% of the less soluble/diffusible inert gas (e.g., 40% N₂ in combination with 60% SF₆); or 45% of the more soluble/diffusible inert gas in combination with 55% of the less soluble/diffusible inert gas (e.g., 45% N₂ in combination with 55% SF₆); or 50% of the more soluble/diffusible inert gas in combination with 50% of the less soluble/diffusible inert gas (e.g., 50% N₂ in combination with 50% SF₆). In certain embodiments, an initial fill gas consisting of 20% of the less soluble/diffusible inert gas with the remainder a more soluble/diffusible inert gas is employed; or an initial fill gas consisting of 19-21% of the less soluble/diffusible inert gas with the remainder a more soluble/diffusible inert gas is employed; or an initial fill gas consisting of 18-22% of the less soluble/diffusible inert gas with the remainder a more soluble/diffusible inert gas is employed; or an initial fill gas consisting of 17-23% of the less soluble/diffusible inert gas with the remainder a more soluble/diffusible inert gas is employed; or an initial fill gas consisting of 16-24% of the less soluble/diffusible inert gas with the remainder a more soluble/diffusible inert gas is employed; or an initial fill gas consisting of 15-25% of the less soluble/diffusible inert gas with the remainder a more soluble/diffusible inert gas is employed. For example, an initial fill gas comprising 18-20% SF₆ with the remainder as nitrogen can be employed, or 19-21% SF₆ with the remainder as nitrogen; or 18-22% SF₆ with the remainder as nitrogen; or 17-23% SF₆ with the remainder as nitrogen; or 16-24% SF₆ with the remainder as nitrogen; or 15-25% SF₆ with the remainder as nitrogen.

Patient diet and medications can also affect/control balloon inflation status—primarily by CO₂ concentration effects produced in the gastric environment. In addition, gastric pH also affects CO₂ concentration. This particular method can also allow for a greater degree of tuning of the device's useful life based on the composite wall material, e.g., barrier/non-barrier and whether the gas that diffuses in is maintained longer in the balloon if it has a barrier wall versus a non-barrier wall. This particular form of self-inflation can be employed using a self-inflating gastric balloon (e.g., initially inflated by a gas generating reaction in the balloon initiated after swallowing), or an inflatable gastric balloon (e.g., inflated using a catheter, with or without endoscopic assistance, delivered nasogastrically or any other delivery method). The method can be used with any gastric balloon, including swallowable balloons and balloons placed in the stomach by, e.g., endoscopic methods. The method is particularly preferred for use in connection with intragastric devices; however, it can also be applied to use in, e.g., pulmonary wedge catheters and urinary incontinence balloon devices. The advantages to this technology include the ability to compensate for stomach accommodation, allowing the balloon to adapt to a stomach that may increase in volume over time, thereby maintaining patient satiety. It also permits starting with a smaller amount of inflation gas constituents for a self-inflating balloon. It can prevent spontaneous deflations by utilizing diffusion gradients between gastric balloon systems and the in vivo gastric environment.

In a particularly preferred embodiment, used in connection with a suitable inert gas such as SF₆ and/or N₂ (with or without CO₂ as an additional inflation gas) as the inflation agent, a multi-layer co-extruded blend for the wall layers is employed. A particularly preferred configuration is Nylon 12/Ethyl Methyl Acrylate/Polyvinylidene Chloride/Ethyl Methyl Acrylate/Nylon 12/Linear Low Density Polyethylene+Low Density Polyethylene (also referred to as co-extruded Nylon 12-encapsulated PVDC-Nylon 12-LLDPE+LDPE multilayer). Another particularly preferred configuration is a co-extruded multi-layer Nylon 12/Linear Low Density Polyethylene+Low Density Polyethylene. Selection of the resins for the composite wall construction (as well as selection of using a coextrusion method or adhesives) can be varied to control compliance (stretchiness), puncture resistance, thickness, adhesion, sealing bond strength, orientation, acid resistance, and permeability characteristics to gasses and water vapor to achieve a particular effect.

Automatic Deflation Of Intragastric Balloon Systems

The self-inflating (also referred to as automatic inflating) or inflatable (also referred to as manually inflating) intragastric balloon is provided with mechanisms to reliably control timing of deflation. In preferred embodiments, the balloon auto-deflates and passes through the stomach, through the lower gastrointestinal tract, and out of the body at the end of its pre-determined useful life (non-spontaneous), preferably between 30 and 90 days but can be timed to deflate within 6 months. In the preferred embodiments described below, the timing of deflation can be accomplished via the external gastric environment (by conditions of temperature, humidity, solubility, and/or pH, for example) or via the environment within the lumen of the inflated balloon. It is preferable for consistency to control the initiation of the self-deflation process by manipulating the internal balloon environment.

In other embodiments, the patch applied to allow for inverted seams as described above and/or one or more additional patches or other structures added to the balloon construction are made out of an erodible, degradable, or dissolvable material (natural or synthetic) and are incorporated into the wall of the balloon. The patch(s) are of sufficient size to ensure opening of a sufficient surface area to cause rapid deflation, and to prevent re-inflation by seepage of stomach fluid into the balloon. The balloon patch(s) comprise materials that can be applied to the balloon such that a substantially smooth surface is maintained, and preferably comprise a single layer or multi-layered material. The patch(s) are constructed using an erodible, disintegrable, degradable or other such material that is preferably tissue-compatible and degrades into non-toxic products or is a material that slowly hydrolyzes and/or dissolves over time (e.g., poly(lactic-co-glycolic acid) (PLGA), poly(lactide-co-glycolide) (PLG), polyglycolic acid (PGA), polycaprolactone (PCL), polyesteramide (PEA), polyhydroxyalkanoate (PHBV), polybutylene succinate adipate (PBSA), aromatic copolyesters (PBAT), poly(lactide-co-caprolactone) (PLCL), polyvinyl alcohol (PVOH), polylactic acid (PLA), poly-L-lactic acid PLAA, pullulan, polyethylene glycol (PEG), polyanhydrides, polyorthoesters, polyaryletherketones (PEEK), multi-block polyetheresters, poliglecaprone, polydioxanone, polytrimethylene carbonate, and other similar materials). These erodible, disintegrable, or degradable materials can be used alone, or in combination with other materials, or can be cast into/co-extruded, laminated, and/or dip coated in conjunction with non-erodible polymers (e.g., PET or the like) and employed in the construction of the balloon. Degradation/erosion occurs, is initiated by, and/or is controlled by the gastric environment (e.g., by conditions of temperature, humidity, solubility, and/or pH, for example), or is controlled within the lumen of the balloon (e.g., by conditions of humidity and/or derived pH, for example) based on what the patch is exposed to. Thickness of the polymer as well as environment which affects degradation and time of exposure can also facilitate degradation timing. Degradation/erosion are timed such that they occur once the pre-determined balloon useful life is completed (e.g., inflation is maintained for from 25 to 90 days in vivo in the stomach before degradation/erosion results in formation of an opening permitting deflation). As an alternative to (or in connection with) using an degradable material for the patch, the patch can comprise a similar fluid retention barrier film or the same film as the remaining wall of the balloon which is adhered to the balloon using a weak adhesive, or welded or adhered such that after a specified amount of time the patch delaminates from the applied area and allows for an opening for inflation fluid release for deflation. Or if deemed necessary for rapid deflation the entire balloon composite wall can be made of the erodible material. The mechanism of using an erodible material or a material that mechanically fails after a pre-specified time is be similar for all embodiments for deflation mechanisms described below as well. The timing of degradation or erosion can be controlled using the external gastric environment (e.g., by conditions of temperature, humidity, solubility, and/or pH, for example) and/or can be controlled by conditions within the lumen of the balloon (e.g., by conditions of humidity and/or pH of residual liquid in the balloon).

In other embodiments, a plug or plugs (optionally in conjunction another degradable retaining structure) can be incorporated into the balloon construction and can consist, all or in part, of an erodible, disintegrable, or otherwise degradable synthetic or natural polymer similar to those described above (e.g., PLGA, PLAA, PEG, or the like). The plug can be formed into various shapes (e.g., cylinder shape) to achieve various surface-to-volume ratios so as to provide a preselected and predictable bulk degradation pattern for the erodible polymer. The plug can incorporate a releasing mechanism that can be chemically initiated after degradation/erosion begins, such that the septum or plug material pops out of the balloon or falls inside of the balloon, thereby creating a passageway for fluid release and subsequent deflation of the balloon. Mechanical additions that can be used in conjunction with a plug include a degradable/erodible/disintegrable material that holds a plug (e.g., of a non-degradable or degradable material) in place or a compressed spring housed within the retaining structure or plug structure. More specifically one preferred embodiment to achieve deflation can comprise a housing, a radial seal, a solid eroding core, and a protective film attached to the external surface of the eroding core. The inside of the eroding core is exposed to the internal balloon liquid. The core creates a compressive force that holds the seal against the housing. As the core erodes, the compression between the housing and the radial seal is reduced until there is clearance between the housing and the seal. Once there is clearance, gas can move freely from the inside of the balloon to the outside environment. The seal can fall out of the housing and into the balloon. The diameter, length, and material types can be adjusted in order to create the deflation at a desired time point. Example materials for each component used to achieve this deflation mechanism can be as follows: Housing: Biocompatible structural material, capable of withstanding enough radial force to form an air tight seal. Possible materials include: polyethylene, polypropylene, polyurethane, UHMWPE, titanium, stainless steel, cobalt chrome, PEEK, or nylon; Radial Seal: The radial seal needs to be composed of a biocompatible elastic material, capable of providing liquid and gas barrier to acidic environments. Possible materials include: silicon, polyurethane, and latex; Eroding Core: The eroding core needs to be a material capable of breaking down at a predictable rate at given environmental conditions. Possible materials include: PLGA, PLA, or other polyanhydrides that are capable of losing integrity over time or any materials listed above that provide erodible characteristics.

For the spring mechanism, once the material degrades, the spring is released and/or the plug/septum is pulled into the balloon or pushed out of the balloon, thus releasing fluid once an orifice has been created by release of the spring mechanism and pushing out or pulling in of the plug.

Another preferred embodiment is comprised of a septum, moisture eroding material inside an inlet port, and moisture absorbing expansion material. The eroding materials slowly erode away when exposed to moisture, eventually exposing the moisture absorbing expansion material. When the moisture expanding material begins to absorb moisture, the expansion pulls the septum out of position in the head by pushing against a septum lip or a ring attached to the septum. Pulling the septum out of position causes an immediate deflation of the balloon. In order to protect the expanding material from moisture until a desired timepoint, the expanding material can be sheathed in water blocking materials, such as parylene, as well as slowly water degrading materials. The moisture contact can be controlled by small inlet ports. The inlet ports can be small holes, or a wick material that draws moisture in a controlled manner. The desired deflation time is achieved through a combination of eroding materials, blocking materials, and inlet port sizing.

In certain embodiments, the balloon can incorporate one or more plugs in the wall of the balloon that contain a compressed pellet or gas releasing pellet. The pellet can be comprised of any combination of constituents that, when activated, emit CO₂ gas (e.g., sodium bicarbonate and citric acid, or potassium bicarbonate and citric acid, or the like). The pellet can be in tablet or rod form protected by an erodible, disintegrable, or degradable material that is preferably tissue-compatible and degrades into non-toxic products or that slowly hydrolyzes and/or dissolves similarly to the plugs and patches described above (e.g., poly(lactic-co-glycolic acid) (PLGA), polyvinyl alcohol (PVOH), polylactic acid (PLA), poly-L-lactic acid PLAA, Pullulan, Polyethylene Glycol, polyanhydrides, polyorthoesters, polyaryletherketones (PEEK), multi-block polyetheresters, poliglecaprone, polydioxanone, polytrimethylene carbonate, and other like materials). Degradation/erosion of the plug initiates the reaction of the two chemicals in the pellet and subsequently leads to formation of gas (e.g., CO₂). As sufficient gas is trapped or built up, sufficient pressure is eventually generated to push out the softened polymer material and create a larger channel for the CO₂ gas in the balloon to escape. External pressure applied by the stomach to the balloon (e.g., squeezing) can contribute to the process of creating a larger channel. Dimensions and properties of the plug (diameter, thickness, composition, molecular weight, etc.) comprised of the polymer drives the timing of degradation.

In other embodiments, plugs or patches of different shapes or sizes similar to those of the plugs described above can be employed within the balloon lumen in a multi-layer configuration including a semi-permeable membrane to facilitate balloon deflation. The plug or patch is made of similar degradable/erodible/dissolvable material as described above (e.g., poly(lactic-co-glycolic acid) (PLGA), polyvinyl alcohol (PVOH), polylactic acid (PLA), PLAA, pullulan, and other like materials) and contains a compartment enclosed by a semi-permeable membrane (impermeable to an osmolyte) that contains a concentrated solution of a solute or osmolyte (such as glucose, sucrose, other sugars, salts, or combination thereof). Once the plug or patch begins to degrade or erode, the water molecules move by osmosis down the water gradient from the region of greater water concentration to the region of lower water concentration across the semi-permeable membrane into the hypertonic solution in the compartment. The compartment containing the osmolyte swells and eventually bursts, pushing the membranes and the degraded plug or patch out, thereby allowing rapid gas loss through the newly created channels or areas.

In certain embodiments, a balloon composed of a septum, moisture eroding material inside an inlet port, and moisture absorbing expansion material is employed. The eroding materials slowly erode away when exposed to moisture, eventually exposing the moisture absorbing expansion material. When the moisture expanding material begins to absorb moisture, the expansion pulls the septum out of position in the head by pushing against a septum lip or a ring attached to the septum. Pulling the septum out of position causes an immediate deflation of the balloon. In order to protect the expanding material from moisture until a desired time point has been reached, the expanding material can be sheathed in water blocking materials, such as parylene, as well as slowly water degrading materials. The moisture contact can be controlled by small inlet ports. The inlet ports can be small holes, or a wick material that draws moisture in a controlled manner. The desired deflation time is achieved through a combination of eroding materials, blocking materials, and inlet port sizing.

Another mechanism for self-deflation is to create a forced de-lamination scheme, which can provide a larger surface area to ensure rapid deflation. In, e.g., a balloon having a tri-layer wall, the outermost layer is substantially strong enough to hold the inflation fluid (e.g., polyethylene terephthalate (PET) or the like), the middle layer is comprised entirely of an erodible material (e.g., PVOH or the like) while the inner layer is comprised of a weaker material (e.g., polyethylene (PE) or the like). The PET or outermost layer is “scored” or hatched with erodible material to create small channels that erode over time. This creates channels such that the gastric fluid seeps into the balloon layers and starts degrading the fully erodible material. When the erodible layer degrades or dissolves, the material that composes the innermost layer also erodes, degrades or dissolves since it is not strong enough to withstand the gastric forces/environment on its own. The balloon then collapses on itself and eventually passes through the lower gastrointestinal tract. Having an erodible layer sandwiched between a strong and weak layer facilitates timing of erosion by creating a longer path length than an erodible plug or patch affected by the gastric environment. The distance between scores or openings can also be selected so as to provide a desired deflation rate.

In another embodiment providing abrupt deflation of the balloon after a desired period of time has elapsed, the composite wall of the entire balloon or a section of the composite wall (patch) includes several material layers that are slowly penetrated by water that has been injected inside the balloon during the manufacturing process or during the inflation process. This water penetrates through the layers, eventually reaching a material that substantially expands, rupturing a thin external protective later, and creating a large hole for gas to escape and the balloon to deflate. The water expanding material is protected from liquid via a coating or sheath, such as parylene, which allows a controllable amount of moisture exposure. Once water reaches the expansion material, it exerts a force on the protective outer layer, causing it to rupture. The outer layer may be created with a weakened bonding area, a partially scored area, or other methods of ensuring a desired rupture location and to facilitate desired timing for auto-deflation to take place. There can be any number of layers between the moist environment and the moisture expanding center. Each material layer can have different erosion rates (e.g., fast or slow) and can be selected by the predetermined time deflation is desired to occur (e.g., after 30 days, 60 days, or more). By varying the number, thickness, and rate of each of the circumferential layers, the time to deflation can be accurately controlled.

Alternatively a pressure sealing button that is adhesively bonded over a perforation in the balloon material can be provided for deflation. The adhesive bonding the button erodes over time when it comes into contact with moisture derived from the gastric fluid or that has been injected inside the balloon. Once the adhesive can no longer bond and create an airtight seal between the adhesive and the button, the balloon will rapidly deflate. By controlling the hole size and moisture exposure of the adhesive, the erosion time can be accurately predicted.

Deflation can also be facilitated by creating a series of connecting ports within the septum or on another similar structure attached to the balloon composite wall. The ports can be constructed using a water- or acid-dissolving, biologically compatible, low permeability substance, such as gelatin. The diameter of the hole, number of holes, channel width, and channel length can all be adjusted to control the dissolving parameters. Once the material in the ports and channel is dissolved, there is a clear path for gas trapped in the balloon to escape, eventually resulting in a deflated balloon. The water can be gastric fluid or controlled internally by including water inside the balloon at assembly or during the inflation process. There can be a plurality of port openings to guarantee gas transmits. Additionally, there are several variables that can be adjusted to control dissolution time: size of the port openings; number of port openings; the length of the internal channel; the width of the internal channel; and the rate of material dissolution. The port/channel layout design can ensure that only a small amount of surface area is exposed to moisture at any particular time, thereby controlling the rate of erosion and ultimately deflation.

A mechanism to facilitate passing involves an erosion mechanism that allows for the balloon to be broken down into a size that has a higher probability of predictably passing through the lower gastrointestinal system. Preferably, the size of the balloon as deflated is less than 5 cm long and 2 cm thick (similar to various foreign objects of similar size that have been shown to pass predictably and easily through the pyloric sphincter). This can be accomplished by providing the balloon with “erodible seams.” One seam that breaks the balloon open into (at a minimum) two halves, or more seams are provided so that a plurality of smaller balloon pieces is produced in the dissociation reaction. The number of seams used can be selected based on the original surface area of the balloon and what is required to dissociate the balloon into pieces that are of a size that can predictably pass through the gastrointestinal tract more easily. The rate of seam erosion can be controlled by using a material affected by, e.g., the external gastric environment pH, liquid, humidity, temperature, or a combination thereof. Seams can be single layer consisting of only erodible material, or multi-layer. The timing of self-deflation can be further controlled by the design of the seam layers, e.g., making the reaction and/or degradation of the seam material dependent on the internal environment of the balloon instead of the external environment. By manipulating the reaction such that erosion or degradation is initiated by the internal environment (e.g., the balloon's internal pH, humidity, or other factors), any impact of person-to-person gastric variability (pH, etc.) that can affect erosion timing is minimized. The internal balloon environment can be manipulated by adding excess water at injection to create a more humid internal environment, or the amount of constituents added can be varied to manipulate the pH, etc.

Film Permeability

A variety of different composite films were tested for permeability of gases as measured by CO₂ diffusion at 37° C., and for suitability for use as materials for wall or other components of the intragastric devices of various embodiments. As shown in the data of Table 3, the permeability of varying composite wall constructions were evaluated and determined by their resistance to CO₂ diffusion rates, where the smaller the permeability test result, the higher barrier to gas diffusion the film provides. As noted, the permeability of the film and degree of barrier the film provides to gas diffusion was derived using CO₂ at 37° C., one of the most permeable gasses. This can be used as a surrogate to other gas diffusion rates where generally CO₂ is 3 to 5 times faster in diffusion across a membrane than oxygen, and nitrogen is 0.2 to 0.4 times faster than the oxygen transmission rate when these are evaluated at 25° C. As Table 3 indicates, permeability of the film is also affected by orientation of the film (which layer is exposed to the CO₂ gas first), and Relative Humidity. The walls were tested under conditions of low relative humidity (0%, representative of conditions inside the balloon upon fill) and high relative humidity (100%, representative of in vivo conditions). In certain embodiments, a composite wall having a permeability of <10 cc/m²/day is generally preferred; however, depending upon the desired effect of inflation and re-inflation by in vivo gasses such as CO₂, a higher permeability of >10 cc/m²/day in in vivo conditions can be desirable. For example, each of the films in the table can be suitable for use in various selected embodiments, such that the resulting balloon wall has a permeability to CO₂ of even greater than >10 cc/m²/day, e.g., >50 cc/m²/day, >100 cc/m²/day, >200 cc/m²/day, >300 cc/m²/day, >400 cc/m²/day, >500 cc/m²/day, >750 cc/m²/day, >1000 cc/m²/day, >1500 cc/m²/day, >2000 cc/m²/day, >2500 cc/m²/day, >3000 cc/m²/day, >3500 cc/m²/day, or even >4000 cc/m²/day. In selected embodiments, it is generally preferred to have a permeability of from about 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 cc/m²/day to about 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140 or 150 cc/m²/day.

In Table 3 and elsewhere herein, various films are listed. When the film comprises two or more layers, a “/” is used to indicate a layer of one material adjacent to another layer, optionally with intervening layers or materials. For example, “AB/C” would refer to a film comprising a layer of A adjacent to a layer of B, and the layer of B adjacent to a layer of C on an opposite side of layer B from the side adjacent to layer A, with or without intervening layers or materials (e.g., tie layers, adhesives, surface preparations, surface treatments, or the like). Referring to the first entry of Table 3, “PE/EVOH/PE” refers to a film comprising a first layer of polyethylene adjacent to a layer of ethylene vinyl alcohol, and the layer of ethylene vinyl alcohol adjacent to a second layer of polyethylene on an opposite side of the ethylene vinyl alcohol to that adjacent to the first layer of polyethylene.

TABLE 3 Innermost Permeability Layer Test Results Film (CO₂ (cc/m2/day) Thickness Exposed (1 ATM/ Film (in) Layer) RH % 37° C.) PE/EVOH/PE 0.002 ± PE 0 10.8 0.001 70% Nylon 6, 66, 0.003 Nylon 6,66 0 2.4 30% MXD6/ EVOH/PVDC/ 70% Nylon 6, 66, 30% MXD6/ LLDPE + LDPE 70% Nylon 6, 66, 0.003 Nylon 6,66 95 ± 5 51.0 30% MXD6/ EVOH/PVDC/ 70% Nylon 6, 66, 30% MXD6/ LLDPE + LDPE 70% Nylon 6, 66, 0.003 LDPE 95 ± 5 3.3 30% MXD6/ EVOH/PVDC/ 70% Nylon 6, 66, 30% MXD6/ LLDPE + LDPE 70% Nylon 6, 66, 0.002 LDPE 0 43.0 30% MXD6/PVDC/ 70% Nylon 6, 66, 30% MXD6/ LLDPE + LDPE 70% Nylon 6, 66, 0.003 LDPE 0 50.0 30% MXD6/PVDC/ 70% Nylon 6, 66, 30% MXD6/ LLDPE + LDPE 70% Nylon 6, 66, 0.002 LDPE 95 ± 5 41.0 30% MXD6/PVDC/ 70% Nylon 6, 66, 30% MXD6/ LLDPE + LDPE 70% Nylon 6, 66, 0.003 LDPE 95 ± 5 49.0 30% MXD6/PVDC/ 70% Nylon 6, 66, 30% MXD6/ LLDPE + LDPE Bi-axially Oriented 0.00125 LDPE 0 15.4 PP/EVOH/PE Bi-axially Oriented 0.00175 PE 0 8.2 PP/EVOH/PE Bi-axially Oriented 0.00125 PE 95 ± 5 282.6 PP/EVOH/PE Bi-axially Oriented 0.00125 PE 95 ± 5 1088.0 PP/EVOH/PE Bi-axially Oriented 0.00175 PE 95 ± 5 235.4 PP/EVOH/PE 0.002 ± NA 0 772.0 Cast PP 0.001 Cast PP/PE/EVOH/PE 0.0025 PE 0 7.2 Cast PP/PE/EVOH/PE 0.0025 PE 0 10.1 Cast PP/PE/EVOH/PE 0.0025 PE 95 ± 5 169.3 Cast PP/PE/EVOH/PE 0.0025 PE 95 ± 5 18.5 Coextruded 0.00125 PE 0 8.1 PE/EVOH/PE Coextruded 0.0015 PE 0 4.9 PE/EVOH/PE Coextruded 0.002 ± PE 0 12.4 PET/SiOx/PE 0.001 CoExtrude-LLDPE/ 0.0025 HDPE 0 1.7 HDPE/EVOH/HDPE HDPE/HDPE/PVdC/ 0.003 HDPE 0 5.0 EVOH/HDPE/ LLDPE + LDPE HDPE/HDPE/PVdC/ 0.003 HDPE 95 ± 5 6.8 EVOH/HDPE/ LLDPE + LDPE HDPE/HDPE/PVdC/ 0.003 LDPE 0 4.4 EVOH/HDPE/ LLDPE + LDPE HDPE/HDPE/PVdC/ 0.003 LDPE 95 ± 5 52.0 EVOH/HDPE/ LLDPE + LDPE HDPE/HDPE/PVdC/ 0.003 LDPE 0 74.0 HDPE/HDPE/ LLDPE + LDPE HDPE/HDPE/PVdC/ 0.003 LDPE 0 47.0 HDPE/HDPE/ LLDPE + LDPE HDPE/HDPE/PVdC/ 0.003 LDPE 95 ± 5 68.0 HDPE/HDPE/ LLDPE + LDPE HDPE/HDPE/PVdC/ 0.003 LDPE 95 ± 5 44.0 HDPE/HDPE/ LLDPE + LDPE Kurarister ™ C, 3 mil 0.003 UNK 0 3.2 Nylon12/PyDC/Nylon 0.003 LLDPE + 0 52.0 12/LLDPE + LDPE LDPE Nylon12/PvDC/Nylon 0.003 LLDPE + 95 ± 5 56.0 12/LLDPE + LDPE LDPE MPI Supernyl LLDPE 0.0022 LLDPE 0 3.3 40 μm MPI Supernyl LLDPE 0.0022 LLDPE 95 ± 5 5.8 40 μm MPI Supernyl LLDPE 0.0026 LLDPE 0 4.2 50 μm MPI Supernyl LLDPE 0.0026 LLDPE 95 ± 5 7.5 50 μm Nylon12/PvDC/Nylon 0.003 LLDPE + 0 59.3 12/LLDPE + LDPE LDPE Nylon12/PVDC/ 0.003 LLDPE + 95 ± 5 29.5 Nylon12/LLDPE + LDPE LDPE Nylon12/PVDC/ 0.003 LLDPE + 0 73.2 Nylon12/LLDPE + LDPE LDPE-Thermoformed Nylon12/PVDC/ 0.0024 LLDPE + 0 77.0 Nylon12/LLDPE + LDPE LDPE Nylon12/PVDC/ 0.0024 LLDPE + 95 ± 5 68.0 Nylon12/LLDPE + LDPE LDPE Nylon12/PVdC/ 0.003 LDPE 0 58.0 Nylon12/LDPE-Cast Nylon12/Nylon Tie/ 0.003 LDPE 95 ± 5 54.0 EVA/PVdC/Adhesive/ Nylon12/Nylon Tie/ LDPE-Cast Nylon12/PVdC/ 0.0035 LDPE 0 14.9 Nylon12/LDPE Nylon12/PVdC/ 0.004 LDPE 0 34.0 Nylon12/LDPE Nylon12/PVdC/ 0.0035 LDPE 95 ± 5 24.9 Nylon12/LDPE Nylon12/PVdC/ 0.0035 LDPE 95 ± 5 41.3 Nylon12/LDPE Nylon12/PVdC/ 0.004 LDPE 95 ± 5 31.7 Nylon12/LDPE Nylon 6, 66/PVDC/ 0.0024 LDPE 0 54.0 Nylon6, 66/LLDPE + LDPE Nylon 6, 66/PVDC/ 0.0024 LDPE 95 ± 5 56.0 Nylon6, 66/LLDPE + LDPE Nylon 6, 66/EVOH/ 0.0032 LDPE 0 5.5 PVDC/Nylon 6, 66/ LDPE Nylon 6, 66/EVOH/ 0.0032 LDPE 95 ± 5 6.4 PVDC/Nylon 6, 66/ LDPE Nylon 6, 66/EVOH/ 0.0032 Nylon 6, 95 ± 5 49.9 PVDC/Nylon 6, 66/ 66 LDPE Nylon 6, 66/PVDC/ 0.0027 LDPE 0 57.0 Nylon6, 66/LLDPE + LDPE Nylon 6, 66/PVDC/ 0.003 LDPE 0 41.0 Nylon6, 66/LLDPE + LDPE Nylon 6, 66/PVDC/ 0.0027 LDPE 95 ± 5 55.0 Nylon6, 66/LLDPE + LDPE Nylon 6, 66/PVDC/ 0.003 LDPE 95 ± 5 46.0 Nylon6, 66/LLDPE + LDPE Multi-layer Nylon 12/ 0.0035 LDPE 0 3203.5 LLDPE + LDPE Multi-layer Nylon 12/ 0.004 LDPE 0 2725.5 LLDPE + LDPE Multi-layer Nylon 12/ 0.0045 LDPE 0 2553.6 LLDPE + LDPE Multi-layer Nylon 12/ 0.0035 LDPE 95 ± 5 2539.3 LLDPE + LDPE Multi-layer Nylon 12/ 0.004 LDPE 95 ± 5 2527.8 LLDPE + LDPE Multi-layer Nylon 12/ 0.0045 LDPE 0 1522.6 LLDPE + LDPE + Parylene Multi-layer Nylon 12/ 0.0045 LDPE 95 ± 5 1275.5 LLDPE + LDPE + Parylene NYLON-SIOX/HDPE/ 0.003 LLDPE 95 ± 5 83.0 LLDPE NYLON-SIOX/HDPE/ 0.003 LLDPE 0 70.0 LLDPE Nylon-SIOX/LLDPE 0.0015 LLDPE 0 134.0 Nylon-SIOX/LLDPE 0.0015 LLDPE 95 ± 5 82.0 OPP Co-extrude with 0.002 mPE 0 5.9 mPE/EVOH/mPE OPP Laminated to 0.0025 mPE 0 4.7 mPE/EVOH/mPE OPP Laminated to 0.003 mPE 0 3.4 mPE/EVOH/mPE OPP Laminated to 0.0025 mPE 95 ± 5 294.3 mPE/EVOH/mPE OPP SIOX/LLDPE 0.002 LLDPE 0 540.5 OPP SIOX/LLDPE 0.002 LLDPE 0 1081.0 OPP SIOX/LLDPE 0.002 LLDPE 95 ± 5 565.0 OPP SIOX/LLDPE 0.002 LLDPE 95 ± 5 594.5 OPP/mPE/EVOH/mPE 0.0021 mPE 0 5.0 OPP/mPE/EVOH/mPE 0.0021 mPE 95 ± 5 437.1 OPP/PE/EVOH/PE 0.0025 OPP 0 8.5 OPP/PE/EVOH/PE 0.0025 OPP 95 ± 5 11.6 OPP/PE/EVOH/PE 0.00175 PE 0 8.1 OPP/PE/EVOH/PE 0.0025 PE 0 8.9 OPP/PE/EVOH/PE 0.0025 PE 0 18.6 OPP/PE/EVOH/PE 0.0025 PE 95 ± 5 259.0 OPP/PE/EVOH/PE 0.0025 PE 95 ± 5 556.1 OPP/PVDC/mPE 0.0017 mPE 0 74.2 OPP/PVDC/mPE 0.0017 mPE 95 ± 5 84.6 OPP-SIOX/LLDPE 0.002 ± LLDPE 95 ± 5 1159.7 0.001 Oriented PA 0.002 ± NA 0 750.9 0.001 Oriented PP 0.002 ± NA 0 726.0 0.001 PA/EVOH/PA/LLDPE 0.0022 LLDPE 0 5.0 PA/EVOH/PA/LLDPE 0.0022 LLDPE 0 3.1 PA/EVOH/PA/LLDPE 0.0022 LLDPE 95 ± 5 10.8 PE/EVOH/PE 0.002 ± PE 0 9.2 0.001 PET 0.001 PE 0 524.7 SiOx-PET/EVOH/PE 0.002 PE 0 1.4 SiOx-PET/MPE/ 0.0016 mPE 0 1.0 EVOH/mPE Si—Ox-PET/PE/ 0.00125 PE 0 1.7 EVOH/PE Si—Ox-PET/PE/ 0.0015 PE 0 1.6 EVOH/PE Si—Ox-PET/PE/ 0.0015 PE 0 5.4 EVOH/PE Si—Ox-PET/PE/ 0.002 PE 0 1.5 EVOH/PE Si—Ox-PET/PE/ 0.002 PE 0 1.8 EVOH/PE Si—Ox-PET/PE/ 0.002 PE 95 ± 5 22.6 EVOH/PE

EXAMPLES

Experiments were conducted to identify appropriate dyes that may be incorporated into their gastric balloon device to function as an indicator for balloon rupture. The characteristics of the dyes considered for selection included the following: acceptable toxicology profile, acceptable solubility, intensely absorbing (high color intensity), stable in the gastric environment, and stable during excretion so as to be visually identified by the patient or a caregiver. The following dyes were identified as possessing the desired properties to make them suitable for use. These included, but were not limited to, fast green FCF (green emission), indigo carmine (blue emission), triamterene (blue emission), senna glycosides (red emission), and betanin (red emission).

The five above-referenced dyes are known to produce either a blue, blue-green, green or red urine color in humans. Methylene blue was also investigated due to its pre-existing use as an indicator for gastric balloon leakage. Patients exposed to methylene blue are known to observe a blue-green discoloration of their urine as the compound is excreted. Two other compounds, Lumichrome and Lumiflavine, also produce blue-green urine but also exhibit poor solubility. Three additional compounds are known to alter the appearance of patient's urine to colors other than blue-green, including red and fluorescent yellow. Drugs known to have the side-effect of coloring patient's urine either blue-green or red were also identified as these might be a source of false positives for balloon leakages.

Methylene blue is a highly emissive blue dye that has found use based on its medicinal properties as well as its redox and emissive properties. The chemical structure of methylene blue is provided below.

As methylene blue passes through the gastrointestinal tract, it is reduced to leukomethylene blue. Leukomethylene blue is stabilized in the urine and excreted mostly unaltered, therefore retaining its intensely blue color. See, e.g., Q. H. Meng, et al. Ann. Lab. Med. 2013, 33, 457-458. Exposure to methylene blue is known to result in patients having their urine turned a blue-green color upon excretion of the dye. Aqueous solutions of methylene blue are approved for the treatment of methemoglobinemia. See, e.g., http ://www.rxlist.com/script/main/rxlist.asp?articlekey=71571&pf=3&page=1. The brand name is Urolene Blue and the typical dosage of methylene blue is 10 mg, but the dosage can vary. Methylene blue is also generally incorporated into sedatives and analgesics, including but not limited to the following (see Q. H. Meng, et. al. Ann. Lab. Med. 2013, 33, 457-458.): Propofol Prosed DS; Rinsapin.

Amounts of methylene blue providing a suitable effect in an intragastric balloon can be as low as 10 mg; however, higher amounts can also be employed, e.g., 15 mg, 20 mg, 25 mg, 30, mg, 35 mg, 40 mg, 45 mg, 50 mg, 55 mg, 60 mg, 65 mg, 70 mg, 75 mg, 80 mg, 85 mg, 90 mg, 95 mg, or 150 mg, 100 mg, 200 mg, or higher. An amount of from about 15 mg to about 60 mg is typically employed, e.g., about 20-40 mg, e.g., about 30 mg. Similar amounts can also be employed for the other dyes identified herein. The dye can be injected into the balloon in a liquid form, e.g., a pure liquid or a solution or suspension in a suitable liquid, e.g., water, ethanol, or any other physiological acceptable liquid, alone or in combination with other pharmaceutically acceptable excipients. Alternatively, or additionally, it can be provided in a solid form, e.g., a paste, a pellet, granules, powder, encapsulated form, or any other suitable form, either in a pure state or in combination with other pharmaceutically acceptable excipients.

BioEnterics Intragastric Balloon (BIB—Allergan Inc. as of 2012) is inflated by injecting saline solution mixed with methylene blue. The methylene blue is incorporated as an indicator for balloon leakage. See “Endoluminal bariatric techniques.” Gastrointestinal Endoscopy 76, 1 (2012). It has been documented that the use of blue-green urine as an indicator for gastric balloon leakage is possible to yield a false positive. In the documented case, a patient detected the indicative green colored urine but did not have a leakage in their balloon. It was concluded that the urine discoloration originated from the use of propofol as a sedative. P. Bernante et al. Obesity Surgery 2003, 13, 951-953.

Table 4 and Table 5 provide information regarding alternative dyes known to color urine.

TABLE 4 Dyes Known to Color Urine Current Use Toxicology Chemical Properties Indigo carmine Colorant for food, nylon, Low level of toxicity by 1.0 g per 100 mL of water (CAS # 860-22-0) surgical sutures, and ingestion: LD50 (rat, (The Merck Index, Fourteenth ingested drugs (Tanya M. oral) = 2 g/kg (Baker Edition, Published by Merck Medina and D. Ashley MSDS sheet) & Co., Inc., 2006) Hill. Am. Fam. Physician (http://hazard.com/msds/ pH indicator-blue at pH < 11 2006, 73, 659-664.) mf/baker/baker/files/ (The Merck Index, Fourteenth Amniotic leakage staining i1440.htm) Edition, Published by Merck (The Merck Index, & Co., Inc., 2006) Fourteenth Edition, Published by Merck & Co., Inc., 2006) Fast Green FCF Colorant for food, LD50 (rat) > 2 g/kg; Very soluble in water, (CAS # 2353-45-9) cosmetics, and drug color may cause eye injury alcohols, insoluble in other additive (FD & C No. 3) (The Merck Index, organic solvents (The (The Merck Index, Fourteenth Edition, Merck Index, Fourteenth Fourteenth Edition, Published by Merck & Edition, Published by Published by Merck & Co., Inc., 2006) Merck & Co., Inc., 2006) Co., Inc., 2006) Lumichrome Light irradiation product None Blue fluorescence (CAS # 1086-80-2) of riboflavin (The Merck Sparingly soluble in hot water Index, Fourteenth Edition, (The Merck Index, Fourteenth Published by Merck & Co., Edition, Published by Merck Inc., 2006) & Co., Inc., 2006) Lumiflavine Light irradiation product None Green fluorescence (CAS # 1088-56-8) of riboflavin (The Merck Very sparingly soluble in Index, Fourteenth Edition, water (The Merck Index, Published by Merck & Co., Fourteenth Edition, Published Inc., 2006) by Merck & Co., Inc., 2006)

TABLE 5 Dye Known to Color Urine Current Use Dose Toxicology Chemical Properties Amitriptyline Tricyclic Depending on LD50 (mice, rats) = Salt is freely soluble Hydrochloride antidepressant treatment, doses vary 350, 380 mg/kg in water and chloroform (CAS # 549-18-8) (TCA) from 10 mg to 150 mg (The Merck Index, (The Merck Index, Marketed drugs a day orally Fourteenth Edition, Fourteenth Edition, include: Vanatrip, (http://www.drugs.com/ Published by Merck Published by Merck Elavil, Endep, monograph/ & Co., Inc., 2006) & Co., Inc., 2006) Levate amitriptyline- hydrochloride.html) Triamterene Hypertension and 100 mg orally twice a Generally well- 1 part soluble in 1000 (CAS # 396-01-0) edema day tolerated in patients parts water(The Merck Diuretic (http://www.drugs.com/ (The Merck Index, Index, Fourteenth Marketed as monograph/ Fourteenth Edition, Edition, Published by Dyrenium triamterene.html) Published by Merck Merck & Co., Inc., & Co., Inc., 2006) 2006) Methocarbamol Skeletal muscle 1500 mg orally four Generally well- Water soluble 2.5 g/ (CAS # 532-03-6) relaxant times a day tolerated in patients 100 mL @ 20 ° C. Marketed as http://www.drugs.com/ (The Merck Index, (The Merck Index, Robaxin monograph/ Fourteenth Edition, Fourteenth Edition, methocarbamol.html Published by Merck Published by Merck & & Co., Inc., 2006) Co., Inc., 2006) Betalain Naturally occurring Approx. 1% (w/v) of None Colored Red (including in beets and other betanin is used Stable between pH 3 betanin) plants commercially as a food and 7 (R. A. Harmer. (bougainvillea, colorant (R. A. Harmer. Food Chemistry 5, amaranth) (The Food Chemistry 5, 1980, 81-90.) Merck Index, 1980, 81-90.) Fourteenth Edition, Published by Merck & Co., Inc., 2006) Senna glycosides Natural stimulant Typically from 25 to None Colored Red (sennosides) laxative; isolated 60 mg per day orally Sennoside A is from rhubarb (The (http://www.drugs.com/ insoluble in water. Merck Index, monograph/ Sennoside B is more Fourteenth Edition, senna.html) soluble in water than Published by Sennoside A (Merck) Merck & Co., Inc., 2006) B vitamins Essential nutrient As part of vitamin Present in all plant Solubility: 1 g in 3 L (e.g. Riboflavin) (The Merck Index, regiment, typically and animal cells in water (CAS # 83-88-5) Fourteenth Edition, 1-2 mg/day minute amounts Aqueous solutions are Published by (http://www vitamins- (The Merck Index, yellow showing a green Merck & Co., Inc., supplements.org/ Fourteenth Edition, fluorescence (The 2006) vitamin-B2- Published by Merck Index, riboflavin.php) Merck & Co., Inc., Fourteenth Edition, 2006) Published by Merck & Co., Inc.)

Other drugs known to have the side-effect of turning urine blue green include, but are not limited to: amlodipine (Norvasc), sildenafil (Viagra), fosinopril (Monopril), Omeprazole (Prilosec), and pravastatin (Pravachol).

Daunorubicin (http://www.drugs.com/sfx/daunorubicin-side-effects.html), phenazopyridine (http://www. drugs. com/monograph/phenazopyridine-hydrochloride.html), and rifampin (http://www.drugs.com/monograph/rifampin.html) are all known to have the side-effect of turning urine red.

Asparagusic Acid (CAS # 2224-02-4, from asparagus) is one of the compounds known to give the characteristic odor to urine after the consumption of asparagus. The odor is due to endocyclic disulfide motif of asparagusic acid (the ring-opened form does not cause the typical odor associated with eating asparagus).

Other sulfide-containing compounds that can produce an odor in urine include, e.g., long-chain thiols such as ethanethiol, which is used as an indicator in natural-gas pipelines.

In certain embodiments, a combination of two colors can create a unique diagnostic. For example, a combination of blue and red emission dyes (such as methylene blue and betalin) can create a unique diagnostic of purple urine if the pharmacokinetics of the dyes are complimentary and they excrete at similar times.

Device 1: An intragastric balloon comprising a device incorporated in the intragastric balloon, the device configured for alerting a patient or caregiver to a failure of the intragastric balloon, wherein the device comprises methylene blue configured to be reduced to leukomethylene blue upon exposure to gastric fluids.

Device 2: Device 1, wherein the failure is spontaneous deflation of the intragastric balloon.

Device 3: Any of Devices 1-2, wherein the failure is leakage of a fill fluid contained within the intragastric balloon.

Device 4: Any of Devices 1-3, wherein the device comprises 10 mg to 60 mg of methylene blue, or 20 mg to 40 mg of methylene blue, or 30 mg of methylene blue.

Device 5: Any of Devices 1-4, wherein the device is methylene blue in liquid form that is injected into the intragastric balloon.

Device 6: Any of Devices 1-5, wherein the device is methylene blue in a solution or suspension in a physiologically acceptable liquid.

Method 1: A method for detecting a failure of an intragastric balloon, the method comprising: introducing, into a stomach of a patient, an intragastric balloon comprising a device configured for alerting the patient or a caregiver to a failure of the intragastric balloon, the device comprising methylene blue; introducing an initial fill fluid into a lumen of the intragastric balloon to inflate the intragastric balloon; exposing the inflated intragastric balloon to the in vivo intragastric environment until a failure of the intragastric balloon occurs, whereby the methylene blue is exposed to gastric fluids and is reduced to leukomethylene blue; and detecting a failure of the intragastric balloon, wherein detecting comprises observing a blue green color in the patient's urine upon excretion of leukomethylene blue.

Method 2: Method 1, wherein the failure is spontaneous deflation of the intragastric balloon.

Method 3: Any of Methods 1-2, wherein the failure is leakage of a fill fluid contained within the intragastric balloon.

Method 4: Any of Methods 1-3, wherein the device comprises 10 mg to 60 mg of methylene blue, or 20 mg to 40 mg of methylene blue, or 30 mg of methylene blue.

Method 5: Any of Methods 1-4, wherein the device is methylene blue in a solution or suspension in a physiologically acceptable liquid.

Method 6: Any of Methods 1-5, wherein the device is methylene blue in liquid form that is injected into the intragastric balloon.

Method 7: Any of Methods 1-6, wherein the device is methylene blue in liquid form that is injected into the intragastric balloon separately from the initial fill fluid.

Method 8: Any of Methods 1-6, wherein the device is methylene blue in liquid form that is injected into the intragastric balloon with the initial fill fluid.

Any of the features of an embodiment of Devices 1-6 is applicable to all aspects and embodiments identified herein. Moreover, any of the features of an embodiment of Devices 1-6 is independently combinable, partly or wholly with other embodiments described herein in any way, e.g., one, two, or three or more embodiments may be combinable in whole or in part. Further, any of the features of an embodiment of Devices 1-6 may be made optional to other aspects or embodiments. Any aspect or embodiment of Methods 1-8 can be performed by a system or apparatus of another aspect or embodiment, and any aspect or embodiment of a system can be configured to perform a method of another aspect or embodiment.

The present invention has been described above with reference to specific embodiments. However, other embodiments than the above described are equally possible within the scope of the invention. Different method steps than those described above may be provided within the scope of the invention. The different features and steps of the invention may be combined in other combinations than those described. The scope of the invention is only limited by the appended patent claims.

All references cited herein are incorporated herein by reference in their entirety. To the extent publications and patents or patent applications incorporated by reference contradict the disclosure contained in the specification, the specification is intended to supersede and/or take precedence over any such contradictory material.

To the extent publications and patents or patent applications incorporated by reference herein contradict the disclosure contained in the specification, the specification is intended to supersede and/or take precedence over any such contradictory material.

Unless otherwise defined, all terms (including technical and scientific terms) are to be given their ordinary and customary meaning to a person of ordinary skill in the art, and are not to be limited to a special or customized meaning unless expressly so defined herein.

Terms and phrases used in this application, and variations thereof, unless otherwise expressly stated, should be construed as open ended as opposed to limiting. As examples of the foregoing, the term ‘including’ should be read to mean ‘including, without limitation’ or the like; the term ‘comprising’ as used herein is synonymous with ‘including,’ ‘containing,’ or ‘characterized by,’ and is inclusive or open-ended and does not exclude additional, unrecited elements or method steps; the term ‘example’ is used to provide exemplary instances of the item in discussion, not an exhaustive or limiting list thereof; adjectives such as ‘known’, ‘normal’, ‘standard’, and terms of similar meaning should not be construed as limiting the item described to a given time period or to an item available as of a given time, but instead should be read to encompass known, normal, or standard technologies that may be available or known now or at any time in the future; and use of terms like ‘preferably,’ ‘preferred,’ ‘desired,’ or ‘desirable,’ and words of similar meaning should not be understood as implying that certain features are critical, essential, or even important to the structure or function of the invention, but instead as merely intended to highlight alternative or additional features that may or may not be utilized in a particular embodiment of the invention. Likewise, a group of items linked with the conjunction ‘and’ should not be read as requiring that each and every one of those items be present in the grouping, but rather should be read as ‘and/or’ unless expressly stated otherwise. Similarly, a group of items linked with the conjunction ‘or’ should not be read as requiring mutual exclusivity among that group, but rather should be read as ‘and/or’ unless expressly stated otherwise. In addition, as used in this application, the articles ‘a’ and ‘an’ should be construed as referring to one or more than one (i.e., to at least one) of the grammatical objects of the article. By way of example, ‘an element’ means one element or more than one element.

The presence in some instances of broadening words and phrases such as ‘one or more’, ‘at least’, ‘but not limited to’, or other like phrases shall not be read to mean that the narrower case is intended or required in instances where such broadening phrases may be absent.

All numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification are to be understood as being modified in all instances by the term ‘about.’ Accordingly, unless indicated to the contrary, the numerical parameters set forth herein are approximations that may vary depending upon the desired properties sought to be obtained. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of any claims in any application claiming priority to the present application, each numerical parameter should be construed in light of the number of significant digits and ordinary rounding approaches. Where a range of values is provided, it is understood that the upper and lower limit, and each intervening value between the upper and lower limit of the range is encompassed within the embodiments.

Furthermore, although the foregoing has been described in some detail by way of illustrations and examples for purposes of clarity and understanding, it is apparent to those skilled in the art that certain changes and modifications may be practiced. Therefore, the description and examples should not be construed as limiting the scope of the invention to the specific embodiments and examples described herein, but rather to also cover all modification and alternatives coming with the true scope and spirit of the invention. 

1-16. (canceled)
 17. An intragastric balloon system, the system comprising: a) an intragastric balloon; and b) a device incorporated in the intragastric balloon, the device configured for alerting a patient or caregiver to a failure of the intragastric balloon, wherein the device is methylene blue.
 18. The intragastric balloon system of claim 17, wherein the methylene blue is configured to be reduced to leukomethylene blue upon exposure to gastric fluids.
 19. The intragastric balloon system of claim 18, wherein the methylene blue comprises 10 mg to 60 mg of methylene blue.
 20. The intragastric balloon system of claim 18, wherein the methylene blue is in liquid form and is injected into the intragastric balloon.
 21. The intragastric balloon system of claim 18, wherein the methylene blue is in a solution or suspension in a physiologically acceptable liquid.
 22. The intragastric balloon system of claim 17, wherein the intragastric balloon comprises a wall defining a lumen, and a self-sealing valve.
 23. The intragastric balloon system of claim 22, wherein the methylene blue has a weight of at least 10 mg.
 24. The intragastric balloon system of claim 22, wherein the methylene blue is injected the balloon lumen in a liquid form.
 25. The intragastric balloon system of claim 22, wherein the methylene blue is provided in a solid form.
 26. The intragastric balloon system of claim 25, wherein the solid form is a paste, a pellet, granules, a powder, or encapsulated.
 27. The intragastric balloon system of claim 17, wherein the failure is spontaneous deflation of the intragastric balloon.
 28. The intragastric balloon system of claim 17, wherein the failure is leakage of a fill fluid contained within the intragastric balloon.
 29. A method for detecting a failure of an intragastric balloon, the method comprising: introducing, into a stomach of a patient, an intragastric balloon comprising a device configured for alerting the patient or a caregiver to a failure of the intragastric balloon, wherein the device is a substance detectable in at least one of urine, feces, blood, perspiration, and breath; introducing an initial fill fluid into a lumen of the intragastric balloon to inflate the intragastric balloon; exposing the inflated intragastric balloon to the in vivo intragastric environment until a failure of the intragastric balloon occurs; and detecting a failure of the intragastric balloon.
 30. The method of claim 29, wherein the device comprises at least 10 mg of methylene blue, wherein the methylene blue is exposed to gastric fluids and is reduced to leukomethylene blue, and wherein detecting comprises observing a blue green color in the patient's urine upon excretion of leukomethylene blue.
 31. The method of claim 29, wherein the failure is spontaneous deflation of the intragastric balloon or a leakage of a fill fluid contained within the intragastric balloon.
 32. The method of claim 29, wherein the substance comprises at least one member of the group consisting of methylene blue, fast green FCF, indigo carmine, triamterene, senna glycosides, and betanin.
 33. The method of claim 29, wherein the substance is injected the balloon lumen in a liquid form.
 34. The method of claim 29, wherein the substance is provided in a solid form, wherein the solid form is a paste, a pellet, granules, a powder, or encapsulated. 